paladin 2 allows turn undead to convert mobs (max 5) through an attribute, they’re not bad for challenge mode (it’s a stationary instance mode that just has you and your party kill stuff within a time limit) but the skill requires there to be mobs to be converted in the first place. Afaik the end game legend raid mobs are all elite and cannot be converted.
EDIT: Restoration is useless in its current state, it only adds natural hp regen (and not even a relevant amount) which doesn’t really work in combat.
There’s no split damage mechanic, there’s an “AoE defense/attack ratio” mechanic though that basically decides how many things can be hit within the range of an attack. It’s not really well polished at this point, as most monsters and bosses just ignore it completely and hit everything within the range of their attack. The system is mostly a limitation only for the player.
Another thing about minions in this game is that they’re very bad at generating aggro or hate or whatever you call it. Their damage is not too strong, and even then it feels like they only generate a fraction of aggro compared to player characters cause it’s way too hard for them to get a monster or boss’ attention even if you only slightly damaged them first. They’re good at pulling mobs though, cause as I mentioned earlier each player can only have around 8 mobs chasing them at a time.
As for Kabbalist, I’ve never really tried it myself but ein sof is one of the best survival buffs for low investment characters. Alongside wiz tree’s Thaumaturge buffs (and linker2 to share ein sof with everyone cause it normally only buffs up to two people), they can let undergeared parties clear content that requires higher atk and def ratings to be able to do efficiently. However when you’re already running with a geared party, cleric and priest heals and revives are probably more than enough to keep the party healthy.
The Kabba number skills also confuse me, better look those up at the intermediate cleric thread or make a new topic/wait for someone else to elaborate here.

As for viable builds with summons, I have two in mind off the top of my head.
First one is the all rounder dps meta right now cleric2-bokor3-druid3-exo2
Exo2 has a low cooldown channeling laser that pretty much fulfills all your dps needs, and while it’s on cooldown you just drop your druid skills to apply dots, heals and even a 15 second invul when needed. Bokor3 gives access to a pretty decent mdef reduction and dark damage increasing debuff using hexing, as well as a self movespeed buff and the zombies themselves. Damballa is also a low cooldown decent damage skill that blows up your zombies, it works well with exo because rubric can easily make zombies to blow up so you just alternate that.
Another build I was thinking of for a more supportive role is Cleric3 Paladin3 Kabba3 +1 filler (Bokor1, Plague Doctor 1, Priest1 or Diev1? anything that’s good at circle 1 really) or Cleric2 Priest2 Paladin3 Kabba3.
I wasn’t able to test these builds during the last reset event unfortunately, but the theory craft behind it is to use barrier’s devotion attribute (you take the damage for everyone inside the barrier) and take advantage of either cleric3’s heal over time or PD’s Healing Factor to keep yourself alive.
The Cleric2 Priest2 variant will give you access to revive and resurrection though, so it’s a bit safer as a support choice but a bit weaker at healing yourself. Oh and Kabba3 allows you to block magic to increase survival even more, but I don’t really know how practical this is since I never got to test it personally.
EDIT: Another thing, healing doesn’t generate aggro in this game