I would certainly ask him about Yasu’s and Lion’s gender. But knowing he wouldn’t ever answer that explicitly for a very justified reason…
There are pretty much 3 questions other than those two:
1- Ask about Erika at Rokkenjima Prime and how the whole thing happened.
2- Ask about Hideyoshi’s backstory and how he lost his family, etc… (I’m very interested on how did his character developed into a cool uncle kind of person after all that).
3- Ask about Ange’s entire timeline of events (one of the most confusing things in the story). Where did she entered the magic part of the story, and what would be its reality counterpart (if there’s any).