Your magical instrument isn't your weapon. I meant one actual weapon aside from that, because you're picking someone who isn't focused on combat and so it would keep variety up.
It's not an issue of power. At all. It's the fact that you picked a bard but proceeded to have rogue, offensive mage, and healer traits piled in, which makes anyone who wants to play those sorts of characters have overlap with yours.
Doing buffs and debuffs is kind of what you do as a bard. I mean, it's not like I'm sticking to D&D definitions or something(Tanya has no white magic but is still a paladin because she's a knight who is part of the clergy) but there's not really any way to have a bard who doesn't focus on playing music that buffs their allies and debuffs their enemies. It's kind of like if someone picks assassin for their class you know what they're going to be doing instantly.