Sequel Possibilities
Xur won't be returning for the sequel
Or he will only be seen at the very beginning long enough for the Ko-Dan Emperor to have him executed. The Ko-Dan Empire invested LOTS of valuable combat resources into that invasion, an invasion Xur assured the Emperor would be a victory for certain. Instead, the invasion fails, all those ships and pilots get blown up, and Xur alone comes back in an escape pod. Nope, he's toast. A sequel will focus on Alex and Maggie's child(ren) and their struggle to live up to their dad's legacy while trying to help end the war.
Since so much time has passed since the original film was released, this is the only plot that could work if it doesn't focus on Louis deciding to follow in Alex's footsteps.