Several questions for partner modification mode

Q1. If the Grenade Launcher is attached to my partner, when I explore and play explosive weapons from my hand as well as announcing my partner is using the Grenade Launcher to attack with, do explosive weapons still get discarded to discard pile or only those explosive weapons that could've been attached to my partner?
Q2. Is the text in some Explosive weapons "(Trash Once Used)" considered as the effect of a card? (The reason behind this question is for David King's level 1 ability from the Outbreak Expansion)
Q3. How does the effect of Hunting Bow WE-048 work when attached to my partner? (Since is attached to my partner and not in my play are, if I declare its use when I explore, does the effect that states "While this weapon is in your Play Area, you cannot play actions" become active?)

1. Yes they go to the discard pile, including any trash once used explosives your partner is using.
2. Yes.
3. Don't know on this one. You might want to post it in one of the FAQs.

It isnt in the play area it is attached to your partner. Therefore you can still use actions