Are any of these questions about the type of additional damage in D&D 5e duplicates?

Question

The following are all related or relatively similar questions about effects that deal damage without specifying a type being combined with effects that deal multiple types of damage at once:

• Can I choose which damage type my Sneak Attack does if my weapon does multiple types?
• When a ranged attack deals multiple damage types, can I choose what damage type my Sharpshooter bonus gives?
• Can a Barbarian choose which weapon die to add for his Brutal Critical?
• If the attack or spell that the goblin's Fury of the Small trait is applied to deals multiple types of damage, what type is the extra damage?
• Can a Zealot Barbarian apply Radiant rage damage?

Are any of these duplicates of each other? Worth noting, the second was recently closed as a duplicate of the first.

Answer 1

No; some of them might have the same answer, but the questions are about different specific features.

doppelgreener's answer to the linked Q&A If an answer to question A can be found in question B, should we close A as duplicate of B? says:

We close Question A as a duplicate of Question B only when all of the following is true:

• It's the same question, or Question A is already covered obviously as a subset of Question B. Obvious here means I can tell at a glance it's there.
• Question B has an obvious answer to Question A. Obvious here means I get a straightforward answer without hard searching — a couple of sentences buried in the middle of a post, or an answer which only sort of implies an answer to Question A, doesn't count as obvious.
• There is not some strong compelling reason to covering Question A alone, separately from Question B. (If the above bullet points are met this rarely happens.)

The idea here is it's the same question with an obvious answer. Someone redirected from Question A to B can see obviously why they were redirected and find a satisfactory answer.

In the case of the questions you're asking about, they're about different specific features/cases. They might have the same answer, but they're not quite the same question. As such, they're not actually duplicates of one another.

If there is a general rule in D&D 5e that addresses all the specific variants of this issue, it might make sense to have a canonical Q&A that addresses that general case, and close the others as duplicates of it, as was done in the following case: What, if anything, should we do about these D&D 5e multiclass spellcasting questions about spell slots?

However, in this case, there is no such general rule. In fact, several of the Q&As you linked rely on the wording of the specific feature in question; some of them note that there is no such general rule on this matter (and thus have to rely on material from outside the rules to support resolving the issue a certain way). As such, even a canonical Q&A for the general case of "What damage type does extra damage do when it's not specified?" would probably not be a good fit here.