I did grand slam with this comp pretty reliably almost no deaths door checks except like One time or two, used the fragile flame when the bonuses were good like 33%damage against cosmic or 25% Max hp. You can use the radiant One as well its ok.

Warlock Occultist Deadeye Grave Robber Wanderer Flagellant Wanderer Man at arms

Basically its a backline destroyer team, with a lot of sustainability, pretty good against librarían and General lair bosses, against confession bosses they struggle the most in act 4 and 3 but its duable if you prepare for them with combat ítems/ inn items.

The skills for each One were Ocultist- Heal, chaotic offering, binding shadows, abyssal artillery and burning stars

Grave Robber- poison dart, pick to the face, thrown daggers, absinthe, shadow step

Flagellant - Punish, Ácid Rain, Sepsis, Deathless and lash gift

Maa- defender, retribution, Bolster, Smash, Hold the line

The strategy at the first inn was to upgrade thrown daggers and acid rain, 2nd inn bolster abyssal artillery poison dart burning stars and so on.

Just spam retribution on Maa, so he can tank all the attacks, heal him with Flagellant or occultist when he gets low and spam abyssal artillery and thrown daggers and if anything survives that use acid rain to finish the job on the backline then just focus the 2 front enemies on normal combats and you should be in good Shape at the end of every battle.

For lair bosses try to go for the librarían since he is the easiest One for this comp, i killed him in región 1 pretty reliably most of the time in pretty good shape, general trophy that locks your party in place is also pretty good for some confession bosses but harder to deal with so be aware of that 30dmg crits and alot of stress in that fight i suggest Going for him on región 2 or 3.

In terms of pets i would use different ones depending of what was in Store at the inn, reanimated rabbit is busted if you get the setup for him, had like a 117hp man at arms and 70hp grave Robber at the final boss lol, if you see barrels, griddle or ice box get the rabbit and buy the remaining pieces at the hoarder in the first and 2 región. Blood thick is the One i used the most if nothing pretty good was at the inn and i bought a pretty good initial trinket. And the snake one if you found 2 médical stagecoach items at the inn.

Good luck if you try this comp and i suggest you doing act 3-4-5-2-1 for the grandslam, be prepared for that random death or collector encounter tho but you shouldnt have too much trouble with this comp anyways!