I like
Tristan, particularly as an alternative to
Christian, which I like but find unusable because I'm agnostic/atheist (depending on my mood :-p). And just to cover all bases, I abhor
Tristan on a girl.
From your combos, I like
Tristan James,
Tristan Wyatt, and
Tristan William.
Tristan Christopher is inexplicably hard for me to say.