Awakening sounds good for Velius. Zalera should come with some buffs for his undead minions- they tend to go down easy, being petrified or itemed to death. Something like Legion: Haste and Regen on all allies, not on self. For Queklain, a close range bad breath attack for his stomach-mouth sprite; Fetid Breath: adds confuse and frog 100%, and other statuses at 25%, but not stop or petrify. I just like seeing the confused frog animation. For Adramelk, Steal Time: Sets the target's CT to 0 and casts stop, cast haste on self.
Hashmalum already has the rare Quake and Tornado spells, right? He's fine as is.