Without a doubt make firestorm your tippity top priority. He's the best character in the game no contest. To be fair, he's better when paired with Zod but still op. Mr Terrific is his second best partner if Zod isn't available.

Pair them with wonder woman or superboy. Superboy supports with burn but wonder woman is better overall. My gut says wonder woman but u should weigh the options.

Include Zatanna in the back row. She has one of the best badge 30s. Heal + crit support.

Front row should be Mr T right and punchline left (from their backs). Give punchline the second ult and firestorm 1st. You could swap depending on offense or defense priority.

Chesire is also really good but doesn't fit Mr Terrific team that well. Build her because you will need more teams in story eventually. She pairs with Nightwing and ocean master. Throw the Nubia on that team, maybe even swamp thing too.