Mm.

I had my own idea for a jonin for Blood O that would contribute to her internal conflict, basically try to keep her loyal to Cloud and emphasize her upbringing over her blood, while the Ishikawas would try to emphasize that she is family when they found out and make her get pulled between them, but that might be a forced conflict and really specific interaction? aaaaagh. but outside of that, no real specifics, so I'm conflicted and biased and don't know what to do about your idea.

and sure, repeated genin failure from Sand, why not.

I mean, the Yuki Clan still exists, they just aren't in a village, where they are is secret (and thus ironically probably fulfilling the defintion of hidden village than any canonical one), so if we ever find out about the guy, there has to be explanation why he is there and not with the rest of them, but other than that, okay, I guess.