How do Rig these accessories (Trims, buttons, etc) on my mesh?

If you applied the modifier it simply stops working.

If you use the hooks properly you will not get any deformation, you probably forgot to clear the previous parenting/weights.

Ah crap. Now that I had applied it already, what can I do? Delete the button and remake it?

If you applied the modifier it simply stops working, so re apply it.

If the addon lets you bake all of its motion to the bones as position/rotation, etc keys, then yes.

Oh, lol. Thank you for that

Sweet, i will give that a try.

@digitvisions @thetony20 @etn249 Thank you all for the advice and support, i think so far it is working as good as it will be. I will push on and see how it goes!