A few questions from a new player

[Fatt_Shade]

Hm . . . it could be bug in your game, but i`m sure Summoner skill from Magic tree boost any summoning ability from units. I know it odes for Rune mages, Royal griffins, and Orc trackers, i just finished game with some of tohse units.
If you haven`t already get 3 lvl summoner, save game and check before and after lvling it checking some unit`s ability.
For droid making with mechanic you can boost up with Neatness skill, in Mind tree, it`s nice boost for them, but only effects 1 unit in game, so think before investing runes.
As for max critical you have 2 choices, as many ppl wrote on this forum, all orc army + paladin for resurrection, or human/elf mix, with royal grifins for +morale and distracting enemy with summons. 3 lvl distortion magic, and precision is a must for both lineups. Human/elf have bonus morale, on other hand goblin lineup have some ridiculous dmg, Aoe from catapults, unstoppable for goblins and lets not forget astral attack for goblin shamans (and they give you new units after every battle-commander talent, so less need to run around islands to restock army).