How does a Rogue’s Expertise feature interact with the Phantom subclasses’s “Whispers of the Dead”?

The Phantom subclass from Tasha’s Cauldron of Everything has the following feature at 3rd level:

Whispers of the Dead
Whenever you finish a short or long rest, you can choose one skill or tool proficiency that you lack and gain it… You lose this proficiency when you use this feature to choose a different proficiency that you lack.

At 6th level, all Rogues get to choose two skills (or thieves’ tools) for expertise:

…choose two of your skill proficiencies, or one of your skill proficiencies and your proficiency with thieves’ tools. Your proficiency bonus is doubled for any ability check you make that uses either of the chosen proficiencies.

Can you apply expertise to a skill gained from Whispers of the Dead, and what then happens if you choose to gain proficiency in a different skill after a rest?

Can you use the occupational expertise die to represent non-occupation-related experience?

In Cthulhu Dark, when you roll to find out how well you do, you roll:

  • One die if the task is within human capabilities.
  • One die if it’s within your occupational expertise.
  • Your Insanity die, if you will risk your sanity to succeed.

In a game I am currently running, the characters are trying to do something that doesn’t exactly fall under any of their occupational expertises (sneaking into the third floor of a house from outside on the ground floor). The character that is doing the sneaking is a con-man specializing in taxidermy, which doesn’t specifically suggest “breaking and entering”, but someone suggested that he did it in the past.

I allowed him to use the occupational expertise die, since it seemed like it would work to represent having prior experience with it, but I’m curious whether I’m correct in using it to represent prior experience that wasn’t directly connected with the character’s occupation.

Can you use the occupational expertise die to represent prior, non-occupation-related, experience when rolling to see how well you do?

Does an Orc fighter have any use for Orc Weapon Expertise?

Gragnar the Mightily Tusked is a fighter. At first level, he took Orc Weapon Familiarity. This makes advanced orc weapons martial orc weapons for Gragnar.

I assume this means that, as his proficiency increases to expert, etc., in martial weapons, he also gains that proficiency with an Orc necksplitter.

But Orc Weapon Expertise states

Whenever you gain a class feature that grants you expert or greater proficiency in a given weapon or weapons, you also gain that proficiency in the falchion, the greataxe, and all orc weapons in which you are trained.

Does Gragnar have any use for this, if the Orc necksplitter is treated as a martial weapon and he therefore gets the proficiency increases?

If not, is this feat more directed at characters who don’t necessarily get increased proficiency with all martial weapons? For example, an Orc Warpriest, who only gains expert proficiency with their deity’s favoured weapon?

Is there an official feat that gives expertise for weapons?

I am playing, as well as about to start DM’ing a one shot, in fifth edition D&D and one of my soon-to-be players has talked to me about making either a Fighter (Samurai) or Monk (Kensei) and was wondering if there was any feat that acted like the Bard’s “Expertise” class feature but for weapons rather then skills.

While I have found some homebrewed content for this, I haven’t found anything official, but I just might not be looking in the right places. Is there something like this or at least a homebrew that is relatively balanced?

Edit: Rather then adding the bonus to attack roll I was looking for something that just effects Damage even if it was a just 1/rest effect. I know that “Great Weapon Master” effect is a -5 to hit, +10 to damage. But I was hoping that there was something like, all attacks deal x2 Proficiency Damage for this turn, 1/rest, so the “Arthur the Archer” example wouldn’t effect his to hit chance just the damage he deals IF he hits.

Does Tool Expertise and Wonder Maker stack? [closed]

I have a Rock Gnome Artificer, which grants Tool Expertise, but I want to take the Wonder Maker feat. Do you add +3 for proficiency, +3 because of Tool Expertise, and +3 because of Wonder Maker when doing a tinker’s tools check?

Tool Expertise

Starting at 3rd level, your proficiency bonus is doubled for any ability check you make that uses your proficiency with a tool.

Starting at 6th level, your proficiency bonus is doubled for any ability check you make that uses your proficiency with a tool.

Wonder Maker

When you make a check using your proficiency with tinker’s tools, you add double your proficiency bonus to the check.

How does Expertise work?

Bards get Expertise at level 3. How does this work?

For example, if I have a standard proficiency bonus of +2, and if I have proficiency in Perception with a Wisdom ability modifier of +2, then my Perception is +4. If I choose expertise in Perception, does it double the +4 to Perception +8, or does it double the proficiency bonus only to +4 for a total of Perception +6?

D&D 3.5 Combat Expertise while under a Daze effect?

Question about Combat Expertise in an intense high-level encounter:

To simplify there are 6 creatures in this fight.

Initiative: P1, P2, Dragon, P3, P4, P5

The enemy is a Dragon that has #3 in initiative. The Dragon has the feat Combat Expertise. (p92 PHB)

Round 1: Turn #1 and #2 occurs. On turn #3 the Dragon takes a full attack action and it uses the Combat Expertise Feat with the action. Turn #5-6 occurs.

Round 2: P1 attacks and deals damage. P2 casts Final Rebuke (p 170 Spell Compendium). The Dragon saves the Will Saving Throw and P2 beats the Dragons Spell Resistance. The Dragon is now dazed for 1 round but it avoided ultimate death. (Correct me if I am wrong up to this point)

Dazed p307 PHB.

P3 then attacks the Dragon that used Combat Expertise. Because the Dragon did not take an action while being dazed does Combat Expertise still apply to the Dragons AC?

Thank you for any input!