Really good hidden, but what justifies him being in a team rather than staying in the village giving out buffs? Like you said he's supportive but not in a traditional sense, he literally doesn't do anything other than majutsu. If I were your opponent, I'd focus on getting you first - kill you, get rid of the annoying buffs (which are REALLY REALLY well thought out I think and pretty original) and kill the team who is now 1 man down.

If you wanna play him like this, relying on the team, that's absolutely 100% fine but I'm just warning you that he doesn't seem to have any proper defense or offense other than ninja tools.