Well then...Suigkarin going to have the most fun. If anyone has any complaints, he just changes. With that being said, I think he’ll be very flexible , now that you mention the water thing. lol
I think I get what your saying. You want them to look like their parents while still having looks that are individually themselves. Or something like that. As for hair styles have you coincided using a grandparents or other relatives hairdo. After all Kankuro parents were a red head and a blond he came out with brown hair. Same with Sakura parents. But really your babies are looking good , I hope you find something for Leegaara's hairdo.
As for KakaNaru, boy or girl good fine. As for the mask, that's up to you I think Naruto be trying to rip it off, out of annoyance. Probably be a hunter ninja. Dog summoner too if you wanted to explore more on dog instead of the frog summons. And for the name all I can think of is Takashi or Sky. If you have anything better go for it.
Again sorry my comments are so long.