I need some clarification when using the feats “Multi-Attack Specialist” with “Combat Follow-Through”
I assume the extra attack given from “Combat Follow-Through” also suffers the same disadvantage as all other attacks given from “Multi-Attack Specialist”, if the later was declared?
When “Combat Follow-Through” is triggered, can its extra attack be used in a bane attack when “Multi-Attack Specialist” was also activated? Or can that attack be used on a bane attack by its own definition?
If any of the above creates different kinds of attacks, in which order would the attacks be resolved?
Yes, Multi-Attack Specialist disadvantage applies to all of your attacks that round regardless of where they come from.
Neither Multi-Attack Specialist nor Combat Follow-through restrict you to “damaging attacks”. Whenever “attack” is mentioned and not “damaging attack” then Banes are allowed.
They resolve in the order they happen. There is no special order here. For example:
You are a gifted swordsman, and you find yourself flanked by two orcs while the rest of your party fights another three. One of the orcs has already been damaged by the magical arrows of your wild ranger friend. On your turn you declare you will be making two additional attacks, for a total of three.
You make your first attack against the damaged orc, bringing it to 0 HP
You immediately make your Combat Follow-through attack targeting the second orc, you miss and with the optional miss rules you choose to inflict Knockdown while he takes a 3 HP chunk out of your armor
You use your second multi-attack at the prone orc. It explodes repeatedly and he dies. Hurray!
Combat Follow-through triggers again, but you have no targets for your blade. The opportunity passes.
You use your move action to get within range of another orc.
You use your third multi-attack.
There is no chance for you to do anything between 1 and 2 or 3 and 4. The only exception is when you have something else that triggers immediately under the same circumstances, such as Combat Momentum, in which case the player chooses which order they happen in.