So it sounds like the consensus is Skyzero's solo variant works well for the base game. Anyone tried it out with the expansion and does it still work?
It works as written if you do not assign Christian a race. You can play as a race though no issues.
For the expansion, I use the leader decks I created. I have a base "action" deck that can be tweaked to behave as you believe the race would have during their reign. Each race has one special action card that goes into the deck as well. Someday I'll get around to scanning and sharing the deck, works well for solo and let's you play the A.I. on autopilot so you can focus on your strategy/tactics.