Holy Hamtaro hamburger in a hamster dam of half-hearted healers.

I'll try my best to answer... but this being the XSP, anything can happen :p

1. Recent notes say 81st generation Valkyrie.
2. The chemical war on Jarodimia began in 2013, and Martel thought she was the sole survivor, IIRC.
3. Meant to be a Dragon Riders reference. (Incidentally: the author of the Taint books was given some false information by an Erinys.)
4. Mayyyyybe? I know AS added a Hiranya Mitsuru clone who goes by her last name (Mitsuru) only. Maybe as a reference, I don't recall.
5. Physics are wonky in Xyrinfe, yes, but each universe has its own laws of physics. :p
As for the other question... I'm assuming suns are stars and thus they could be star systems? (I'm no good with this sort of thing and Kim says "others decide their answers", so.)
6. They're all born after 2018, and aren't a joke. :p
2019: Evelyn and Terri
2021: Leanne, Blake, Xenobia, Julie, Kaitlyn
2022: Faith and Elesis
2023: Cinder, Vera, Narcissa, Quinessa, Gina
They're all Valkyrie and Evan's daughters. (They've got lengthy full names because Valkyrie likes long names.)

7. Yes. (Unless you guys decide "no". :p )