Paint Grenade, like every other grenade, is in the Gear section for a bunch of legacy reasons that aren't very interesting, but are very tedious to fix.
In Debt is annoying and vague and I hate it. Unfortunately it's vague enough that I want to see an errata comment on it, because as is I'm not sure whether it's supposed to behave in the same way as other negative qualities.
As for the drake knowledge skill, I can't replicate it, so I'd need to see the error or the character file.