I'm afraid special races are off the table, players can only play as the race they've selected from character creation (or ones they transform into like Liches, Vampires, etc.) In this case, you'd just be a Lupine rather than a youkai spirit reincarnated as a Lupine.
While flavouring Youkai as others is fine. For instance, if you wanted to give your Byakko a different name and describe it as a lightning wolf instead of a tiger. That's acceptable.
But I'd say avoid making direct parallels to mythology though; use a different name and avoid references to the mythos they're from. Sure, while some Youkai like Byakko and Seiryuu exist and have their original concepts based on mythology, that doesn't necessarily mean other mythical creatures/deities exist as Youkai.
As for whether reincarnation is actually a thing? I don't believe there's any mention one way or the other. That said, I don't think I should approve anything to do with actual reincarnations at this point. It's fine to hold it as a personal belief for the character but not in actual fact.
I'd say it would make more sense to have this lightning wolf Youkai as one the character has contracted (either as a Guardian Spirit or a less personal one from the usual treaty with one) with the mild electrical aura as a feature of that Youkai, much like how other Youkai often provide a passive benefit with the Sync-Mind skill.
While flavouring Youkai as others is fine. For instance, if you wanted to give your Byakko a different name and describe it as a lightning wolf instead of a tiger. That's acceptable.
But I'd say avoid making direct parallels to mythology though; use a different name and avoid references to the mythos they're from. Sure, while some Youkai like Byakko and Seiryuu exist and have their original concepts based on mythology, that doesn't necessarily mean other mythical creatures/deities exist as Youkai.
As for whether reincarnation is actually a thing? I don't believe there's any mention one way or the other. That said, I don't think I should approve anything to do with actual reincarnations at this point. It's fine to hold it as a personal belief for the character but not in actual fact.
I'd say it would make more sense to have this lightning wolf Youkai as one the character has contracted (either as a Guardian Spirit or a less personal one from the usual treaty with one) with the mild electrical aura as a feature of that Youkai, much like how other Youkai often provide a passive benefit with the Sync-Mind skill.