My guess is Sova, Brim, Cypher, Kay/o and Omen
Soulcas is best at Fade and Astra but can play Kay/o and Skye
Scream will play Entry but can flex to kay/o and sage
Jamppi is best on Breach and Chamber but plays a lot of Omen and has ability to play Jett, KJ, and Sova
Nivera will always play one of Viper Chamber KJ
That leaves them with an obvious hole at Brim and Sova as well as him probably needing to pick up Kay/O on maps like Ascent or IB and Omen when Jamppi is on Breach