Slightly on/off topic but from another video game Mass Effect, your pilot for all 3 games can't use his legs at all. He gives alot of info and backstory on his disease but it still doesn't stop him from being one of the best pilots in the game.
Having disabilities isn't a problem especially when modern or future tech can help solve the problem. It also depends on the universe that it is set in. Were i see it, the SW universe has plenty of I option where people like Drogon can get by fine. I can see how Drogon would be part of the Rebellion and be Frontline. One missing finger isn't too much of a hinder and Rebels aren't too picky on their roster choice. Considering probally alot of recruits still went empire, the Rebellion couldn't afford to turn away people. This is true even in real modern conflicts were people are rebelling. Everyone who wants to rebel will, not just the inshape fighting force.