⚔️Serberia

In short, we have: Rohey, Gulveig, Kalentia, Veserod, Shino, Dubinkin, and possibly Anders and Anselm with Renold. That's 6-9 units. If Veserod takes the leadership role, he won't waste a unit slot, but he might get a buff. Regarding pairings: Retribution doesn't seem like the most useful option in this battle.

Gulveig and Kalentia are a praying duo, supporting each other, as seen in this video.
I would advise Anselm to pray (but Aretz will probably choose that anyway, as it's supportive and role-playing-friendly) for Rohey, if he's going to be the third tank, and his ability works well with prayer.
Shino will likely motivate someone; I don't see any other options for her. She probably won't have many choices besides Veserod.
Anders and Daniel can be a strike duo. Alternatively, Daniel could try taking Retribution and applying it to Rohey, while Rohey buffs him in return. This would be a more damage-focused strategy. Anselm would then have to pray for Shino. Anders would then only have Anselm and Renold as targets, but they wouldn't benefit much from unity buffs in this battle.
I'm not sure what Renold will be doing, as sending him into melee against the golem is very risky. He could stand back and watch, then pull our corpses away. Or, if the player wants, he could run into melee and provide a minor DPS boost.