OK, cross-universe term aside, I'm actually talking about playing a former Separatist. Whether from a Separatist Remnant or just an ideological convert, it would make an interesting angle that's not quite the same as being a member of the Rebellion (you want to overthrow the Empire, but you're not keen on restoring the Republic). Despite having been run by greedy mercantile groups and manipulated by the Sith, there were many well-intentioned beings that felt that independence was a worthy goal.
I was looking at a few possibilities such as a Droid Hired Gun (Mercenary Soldier) that is a veteran of the Clone Wars, or a young Human Colonist (Politico) that still seeks to spread the Separatist position (what they publicly preached, not the secret Sith agenda) of his late father.
Any thoughts?