Well I dont know bout your build and gears, but honestly your level might pull you down, since you will be taking more damage when few level lower than the enemies, as I remember divine is at lvl34.
I kill him easily solo without any creature or summoning, with less than 5 hp potions. Therefore I really cant suggest an appropriate strategy to you. You can either decide to take down the divine 1st, which should the 1 which inflict most damage to you or take down those summoner and healers paladin. Use your summon and necromantic creature to help you with the fight
I dont know what game you have been playing but it for sure not the same as i have done. i had my pet out and he have 2.8k hp and they used less then 5 seconds to kill him, i was lvl 34 when i killed them. i used +40 potions and i had 937hp, evade talents max out, talents in defensive posture and had talents in potions, best gear that have been droping for me with bests enchantes and charmes. my way to kill them was for them to kill them self so i charmed the adds and kite'd and helped out when i thought it was safe from polymorph, stun attacks and sleep. just standig still in a corner was impossible for me since they never whent under 50% they always healed, and the incomeing dmg was to high from the group to take, even with max out life leech and enchant on my sword and spaming healt potion. when the adds was down it was easy enough. the divine was oom after 1-2 minuts fight with him alone so no more heals, and zandalar was hideing behind a pillar so i didnt have to worry about him.
1st of all I dont know your build, your defense and your skills. That is what I experience when facing him at lvl 35. All my defense reach 60%+ with the use of potions. Those paladin hit me for crap damage even I try set difficulty to high. With 2 to 3 points in potion mastery, my rank 10 hp pots heals me fully when my hp manage to drop to 50%, when I had 807 hp. My weapon damage is 561-682 + (290-290). With rank 1 battle rage, it reach 643-782 for normal damage. With rank 10 thousand strike, my crit damage on divine reach above 1k. If half of the hits turn out to be critical, he usually just lay dead on the ground. If he survived, a few more whack and his gone, where I usually kill him 1st over the others, since he will usually rush to me asking to die. My char is a critical dual wield warrior. My evade just rank 1 from ultring set if not mistake, as I see the increment is extremely little even has high rank on it. I can upload the save and you can go try it out if you really want to.
PS: oh ya you mentioned on the pet creature, my 1st try on medium difficulty, I went in together will my pet as well. As like you mentioned, my pet just die extremely fast, so I didnt bother on summon it anymore.
