Round table

They could cast all the spells at once, as long as they don't interrupt each other like slow/haste. If it was limited to only 3, how would Aura of Divinity work? :D

Does this not apply to units that cast spells? I often remember casting with Gremlins: 1 Flash, 2 Shield, 3 Hide, 4 Haste, and Flash would expire (all in one round).