No, it's fine. Choose the character you're the most comfortable with. My only request is that we fight on Hoth, so you may want to choose your character accordingly. No vehicles though.
Mm... After I finish some NPCing in another thread, I can NPC some Imp forces. I'm assuming it's on Muunilinst since that's where it occured. Have you mentioned anything to Xeno about what you have in mind, just so Imp involvement has been cleared with an 'okay'?
I'd suggest asking someone who had some involvement on the other side of that original bombing to NPC for you. Somebody who was involved originally would know exactly what you'd find.