Love this. I still think there's mileage in a mixed arms style of minion army instead of the usual "more of one type better" approach. Examples like this of force multipliers are so cool - can't wait to see some theory crafted synergy squads that really let them shine.
Maybe a combo of lich for unholy might, twilight officer for more damage, clerics to heal, frost mages for CD based armour and frost thorns and then zombies or unearth for main dps for all of those to buff...
I had good success with combinations of themed spectres last league (it that shreds with the massive stabby guy from breach, or harpies with demon leapers in corrupted maps for instance) and suspect there are some broken combos that haven't been pulled out yet!