[@Skwint] Howdy Skwint. Immediate bonus points for making me think of Robert Shaw's character from Jaws when I read your name. 

As to your question -- I'm not looking to "fill" any rolls, per se. I will assume that anyone who crews aboard a tramp freighter knows how to take care of themselves, either with blasters or bladed weapons. There are literally a thousand options. Spice dealer? Medic? Slicer / Hacker? Courtesan? Ex-slave? Miner? Archaeologist? Hunter (of people or otherwise?) Trader? Merchant? Muscle? Merc / gun-for-hire? Droid? Passenger? Preacher? Ex-Military? The list is endless. 

My only advice would be, play something that you can pull off. Nothing worse for your in-character swagger than being a mechanic who can't fluently speak the SW engine lingo, or a Medic who knows nothing about anatomy. Just makes it harder for you, the writer. Door's wide open. C'mon in and play.