I don´t recomment gnolls, they ain´t smart or honorable enough, since there just like wolfs they´d attack you if you get too near.
No humanoid in the neutral section that you can actually use as ally´s except Golems they are magicly animated. (Humanoid: everything that has atleast two legs standing uprights and has atleast some language of there own, the nerubian are humanoid i think although they look like insects.)
When making an army don´t make them too random there must be some order and don´t make them too many an army with over 20 diffirent types of units is way too much atleast the maximun should be 15.
If you wish you can add goblin mercs to your ranks has hireble units.
Hers some ideas.
Human Footman\Dwarf Fighter
Dwarf Rifleman or a Human Archer\Rifle
Dwarf\Human priest\cleric
Cavalier\Knight\Paladin\Crusader
Avenger
) )
Exorcist (A priest which specialises in damaging the undead)
Gnome Alchemist (I throw fiery potions jejiii kaboom)
Gnome Engineer (Repairs mechanical structures & units, a decent fighter]
Steamtank\Cannon\Catapult\Ballista Wc2 style
Pyromancer (firemage)\Cryomancer (frostmage)\orgymancer (Eroticmage) (haha i made a joke for the last one, or did i?)
Still need more?