How does underwater rules work with flying familiars?

I will soon run the Underworld Speculation adventure with my group of players and two of them have flying familiars. An owl and a pseudo dragon.

Is there something in the rules that states that a familiar or a flying familiar can’t be used in water ?

There isn’t any rule change or anything about underwater fight and exploration. PC group is able to breath underwater thanks to a NPC that casts Water Breathing.

What on earth does the wizard’s “Familiars” feature do?

DCC Core Rulebook pg. 49

Familiars: More than one wizard has found comfort in the company of a black cat, hissing snake, or clay homunculus. A wizard may utilize the spell find familiar to obtain such a partner.

For the life of me, I can’t figure out what this means. I can only see 3 plausible interpretations:

  1. Wizards automatically learn the find familiar spell, in addition to his other spells. This explanation doesn’t seem right since this feature is phrased so differently than the elf’s “Supernatural patrons” feature.

  2. Elves cannot learn the spell find familiar, since they don’t have the “Familiars” feature.

  3. This feature does literally nothing. In that case, why is it even there?

Does the Voice of the Chain Master invocation allow me to see through my familiar’s senses without using an action?

After reading this Sorlock guide and a further discussion in the comments about this topic, it’s still unclear to me if the Voice of the Chain Master invocation lifts the requirement of spending an action to perceive through the familiar’s senses.

The relevant part of the find familiar spell says:

While your familiar is within 100 feet of you, you can communicate with it telepathically. Additionally, as an action, you can see through your familiar’s eyes and hear what it hears until the start of your next turn, gaining the benefits of any special senses that the familiar has. During this time, you are deaf and blind with regard to your own senses.

The warlock’s Voice of the Chain Master eldritch invocation says, in part:

You can communicate telepathically with your familiar and perceive through your familiar’s senses as long as you are on the same plane of existence.

They invoke an explanation from Jeremy Crawford which, to me, doesn’t clarify anything at all:

Voice of the Chain Master enhances the find familiar spell, which otherwise works as written for the warlock.

To me, “enhances the find familiar spell” could either mean solely that it increases the range at which you can perceive through the familiar’s senses (or communicate telepathically), or that it both enhances the range and also removes the need to use your action to perceive through its senses. But again, this depends on how you read it.

Does Voice of the Chain Master remove the action usage requirement from find familiar? How are you arriving at that answer?

When did familiars stop giving bonus hit points?

When I first started playing D&D, familiars used to give their Wizard bonus hit points equal to the familiar’s own hp.

For instance, if your familiar had 2 hp, you got a bonus 2 hp. However, if your familiar died or was killed, you lost double its hit points. At the time, Wizards had a d4, so losing your familiar could literally kill you at low levels.

When did familiars stop giving bonus hit points?

What spells can familiars use?

I have a question regarding familiars gained through Find Familiar for non-Warlocks.

Finally, when you cast a spell with a range of touch, your familiar can deliver the spell as if it had cast the spell.

I’ve read a number of places where people suggest that there are a number of touch attack spells that can be used, but I can find only three: Shocking Grasp, Inflict Wounds, and Forbiddance.

Are there other spells that are allowed?

Can spells with a range of Self be cast via a familiar?

When does a Chain Familiar’s attack occur using the new UA Eldritch Invocation: Chain Master’s Fury?

  1. The familiar attacks immediately using the Warlock’s bonus action.
  2. The familiar attacks immediately, using the familiar’s reaction.
  3. The familiar attacks, on the familiar’s turn, using the familiar’s reaction.

Eldritch Invocation: Chain Master’s Fury Prerequisite: 9th level, Pact of the Chain feature. As a bonus action, you can command your familiar to make one attack.

Perception checks through a familiar’s eyes

If I cast the find familiar spell and summon a familiar, then I can look through my familiar’s eyes, hear through its ears, and communicate with it telepathically. (It is not a blind or deaf creature. If the question of whether it can understand my thoughts is an issue, then assume I am a warlock and my familiar is an imp.)

I tell the familiar to stop for a moment so I can make an active effort to concentrate on what I see and hear. Therefore, I roll a Perception check.

Do I roll it with the familiar’s perception modifier, or my own modifier? Or one roll for me and one roll for the familiar?

Do familiars reproduce? If ‘yes’, what kinds of offspring result?

The spell Find Familiar summons a simple yet common creature of the caster’s choice (like a cat, rat, raven or weasel). Such a creature’s organs all function healthfully, including eating and sleeping. This creature is not a beast however:

Appearing in an unoccupied space within range, the familiar has the statistics of the chosen form – though it is a celestial, fey, or fiend (your choice) instead of a beast.

Can a coupling of (matching) summoned familiars reproduce? If ‘no’, why so? If ‘yes’, what offspring is produced (a ‘common’ beast, some 1/2 beast + 1/2 spirit hybrid or one of the three types of spirits)?

How does the contingency spell interact with familiars in D&D3.5?

Contingency is a personal range spell which lasts until some arbitrarily-defined condition triggers it. At that point it casts another “companion” spell, “which affects your person” and ends. If you try to cast a second contingency spell while the first is still active, the first is dispelled. You must carry an expensive ivory statue of yourself to make the spell work.

Familiars have the Share Spells ability: anything a wizard casts on himself can also affect the familiar (as long as it stays inside 5 feet).

So what happens when I try to share contingency? – Does the familiar need his own tiny statue? – Does the companion spell need to be the same for both? – If the Wizard discharges his contingency, does the familiar still have a contingency active? Vice versa? – If so, what happens if the wizard casts contingency again?

I’m primarily looking for Rules-As-Written answers here. Experience with or analysis of how an interpretation works in play would also be interesting.