Okay, lets lets look at these:

1- Uchiha/Hyuga hybrid is fine since its not a Senju/Uchiha one. backstory makes sense. I can see Root using him for their ends in some capacity. also playing out the difficulties of trying to juggle two different eyes that aren't entirely compatible with each other might be fun to see.

2-the delightful ninja creeps are a cool concept to, I'm just not sure: where would they be from? Igor didn't specify where the sound five type of stuff are in this Sound Village, so.....default assumption is that they're Sound and that Sakon/Udon's bloodline is either a clan we haven't specified or from somewhere else. so we'd have to come up with a clan for that and what that clan's position and goals are in Sound if any- make sure they make sense given the history and environment they are in, all that sort of thing. like if they were willing to make kids like this, clearly they value things over the kids freedom or a normal lifestyle.

3-Menko
ah, statting out a snake summon? that makes sense. some summons are probably more versatile and powerful than others after all. seems like a good thing to put in for Senko.