How exactly does a Changeling’s shapeshifting work?

Though I have asked a similar question here, and I am very thankful for NautArch’s answer, I realized that the more I looked into the text of a changeling’s shapeshifter trait, the more questions I had as I am not quite understanding their limitations and specifications.

To reiterate the text:

As an action, you can change your appearance and your voice. You determine the specifics of the changes, including your coloration, hair length, and sex. You can also adjust your height and weight, but not so much that your size changes. You can make yourself appear as a member of another race, though none of your game statistics change. You can’t duplicate the appearance of a creature you’ve never seen, and you must adopt a form that has the same basic arrangement of limbs that you have. Your clothing and equipment aren’t changed by this trait.

The first part of the confusion I have is knowing what exactly you can change into. Adjusting height, weight, color, (gender, hair length), and race so long as they are a medium creature sounds simple enough, but does this mean you can be any creature with 4 limbs in a medium-size? From a medium minotaur to a wolf? From a Babau to an animated armor? What about see-through creatures like Shadows?

The second part of the confusion is understanding the nuances of how sizing works. While I realize that the basic rules focus on player space, I found that the System Reference Document of 3.5e seemed to comply with 5e’s guide when checking playable race height guides, so good as a guide to find out how tall/short I can make my changeling.

According to that, a changeling can be anywhere from a 4ft 60lbs character to one of 8ft and 500lbs. However, as a changeling’s stats don’t change and things like speed and lifting strength are not tied into the size of a creature, does this mean that your changeling monk with the mobile feat and a +1 strength (for instance) could appear to be a 4′ dwarf weighing 60lbs carrying 225lbs at 60ft per round the same as an 8′ tall goliath with 500lbs of pure muscle unable to do any better?

I realize that these examples might seem exaggerated, or quite different, but there are there to highlight the confusion that I still have with the changeling’s feature; the monster type is described in 3 vague ways (descriptors, race, creature) leaving little understanding to the limitations, the stats remaining the same seem odd if one can gain or lose muscle mass, and I can’t seem to wrap my head around it.

Last note, I realize this question is quite similar, but I am still confused and was hoping for a bit of clarification.

Are there ways Changelings can overcome their shape-shifting limitations?

While the changeling’s shapeshifting ability does provide the player with quite a variety of creatures (both pc and npc) to choose from, the rules do limit it to medium human-like (as humanoid is a type) creatures lacking tails, horns (and arguably horns).

As an action, you can change your appearance and your voice. You determine the specifics of the changes, including your coloration, hair length, and sex. You can also adjust your height and weight, but not so much that your size changes. You can make yourself appear as a member of another race, though none of your game statistics change. You can’t duplicate the appearance of a creature you’ve never seen, and you must adopt a form that has the same basic arrangement of limbs that you have. Your clothing and equipment aren’t changed by this trait.

However, I am left to wonder if this means that the changeling is barred from accessing the image of nearly half the PC list, or if the wording of "a form that" suggests there are ways for a changeling to overcome their limits, relying on RAW?

For instance:

  • Could a changeling personalize the visage they use beyond the race’s traits, such as a Drow with black hair, a shifter’s shifting features, or a tiefling that lost its tail?
  • Could a potion of giant size, or the Enlarge-Reduce spell allow a changeling to temporarily dip in the visages of other races?
  • Would consuming "Blood of Lycanthrope" give them access to the tail due to the hybrid form?
  • Are there any feats yet in 5e that can allow the changeling to upgrade his shifting from alter-self like to disguise self like?

As a side question, I noticed that changelings don’t appear to have darkvision like their doppelganger cousins(?) do. Did I miss this point or would this also apply a disadvantage to the kinds of masks a changeling can effectively use?

How do the physical traits granted by the draconic sorcerer bloodline interact with a changeling’s shapechanger trait?

Sorcerers with the draconic bloodline develop a thin sheen of dragon-like scales and can eventually manifest wings. How does this interact with the changeling’s ability to alter their shape?

For instance:

  • Can they maintain the armor bonus of draconic resilience when they are mimicking a race without scales?
  • Can they manifest wings and then change them to match an Aarakocra or Winged Tiefling while still maintaining their original flight speed?

How much can changelings alter the length of specific body parts?

Like with disguise self, changelings can alter their total height by 1 foot. So they could make both their legs 1 foot shorter, and that would work. In theory, they could even turn both their legs into little stubs, with a 1-inch-tall torso, as long as they elongate their neck to be about 5 feet long.

But what if a changeling wanted to take on the guise of a certain pirate, who’s missing a single leg? In other words, leave their total height the same and keep one leg the same length, but make the other leg into a little stub. That’s a change of more than 1 foot (erm, so to speak), but it isn’t explicitly a change to their height, since their remaining leg determines how tall they stand.

That much can also be asked about the spell, but changelings add on the twist that the alterations are actual physical changes. So is there any difference in the situations between changing the length of a leg, and changing the length of body parts that don’t contribute to height?

That is to say, is there anything stopping a changeling from growing out 50 feet of hair so the party can cut it off and use it as a rope? Or, similarly, causing their arm/fingers to become 50 feet long to manipulate items from the opposite side of a room? Or causing their tail to grow from 0 inches to 50 feet for no particular reason other than giving me another body part example for presumably the same rule?

And then, what about doing all of the above at the same time?

image included to demonstrate what exactly I mean

Are unwilling Changelings now immune to the Polymorph spell if using the stat block in Eberron: Rising from the Last War?

In the original question Are Changelings immune to the Polymorph spell?, it was decided that because Changelings didn’t have the Shapeshifter trait (though the answer should have said Shapechanger) Polymorph would still work on them. Now, with the release of Eberron: Rising from the Last War, Changelings have the following trait:

Shapechanger. As an action, you can change your appearance and your voice. You determine the specifics of the changes, including your coloration, hair length, and sex. You can also adjust your height and weight, but not so much that your size changes. You can make yourself appear as a member of another race, though none of your game statistics change. You can’t duplicate the appearance of a creature you’ve never seen, and you must adopt a form that has the same basic arrangement of limbs that you have. Your clothing and equipment aren’t changed by this trait. You stay in this new form until you use an action to revert to your true form or until you die.

And with Polymorph’s description:

This spell transforms a creature that you can see within range into a new form. An unwilling creature must make a Wisdom saving throw to avoid the effect. The spell has no effect on a shapechanger or a creature with 0 hit points.

With Changelings actually having this trait, do they automatically pass Polymorph’s saving throw and remain unaffected? This only pertaining to unwilling Changelings, of course.

Are Changelings immune to the Polymorph spell?

The Polymorph spell says:

This spell transforms a creature with at least 1 hit point that you can see within range into a new form. An unwilling creature must make a Wisdom saving throw to avoid the effect. A shapechanger automatically succeeds on this saving throw.

Changelings, which are similar to doppelgangers, are able to change appearance, but don’t seem to be explicitly shapechangers. Are changelings actual shapechangers and therefore immune to Polymorph?

EDIT: Referring to the official changelings, not the UA ones.

Are Changelings immune to the Polymorph spell?

The Polymorph spell says:

This spell transforms a creature with at least 1 hit point that you can see within range into a new form. An unwilling creature must make a Wisdom saving throw to avoid the effect. A shapechanger automatically succeeds on this saving throw.

Changelings, which are similar to doppelgangers, are able to change appearance, but don’t seem to be explicitly shapechangers. Are changelings actual shapechangers and therefore immune to Polymorph?

EDIT: Referring to the official changelings, not the UA ones.

How does a changeling’s Divergent Persona affect bard spells cast using musical instruments?

My character is a level 1 Changeling Bard. In my character’s story, his Bard personality is what I’m using for his Divergent Persona racial feature. So it says under the description for divergent persona that I can select “one tool of your choice” for which “the related proficiency bonus is doubled” which I chose as his instrument he uses for his spells.

Does this mean he gets the double proficiency bonus when he casts spells using that instrument? Or is it more in regards to performance checks and such?

It does finish off saying “the related proficiency bonus is doubled for any ability check you make that uses that proficiency”. However I think the proficiency bonus I gain from spells doesn’t come from my instrument and is instead just my natural proficiency bonus. But theoretically I am still using the instrument to make that spell ability check, so how does this work?

Either way I’m stumped, if anyone is able to logically state an answer for me, I’d be ever grateful!