Telluria is arguably the best tank in the game… She’s fun on offense too.
If he had everything maxed, I’d probably go:
Jabber - Rana - Telluria - Vela - JF/Natalya.
Out of what’s already maxed…
There’s only one top tier tank there and it’s Kunchen.
Rana flanks well, Poseidon does too… Then again, Anzogh and Richard/Isarnia can work at flank but you don’t really want any of them on wings. Kingston and Morgan both make good wings but you won’t really want both.
I’d probably forego rainbow temporarily and run something like: Poseidon - Anzogh - Kunch - Rana - Morgan
Strong wings, appropriate flanks, a good tank and secondary healer… And makes good use of emblems where they are now.
Longer term, those emblems are going to want to come off Perseus (who’s pretty useless) and go towards Telluria.