After testing out the summons in Act 5, I changed my decisions. The demon makes a terrible mage, and the Raanaar isn't that great a fighter.
I gave the Demon enough levels to reach level 30, and the Raanaar skeleton enough levels to reach level 40.
I put every single point of the Demon's skill points into Constitution. His role is a walking shield. He can't actually hurt anything, but with him in the lead, he draws a large group of enemies to him, perfect for Explosive Arrow.
I wasn't paying close attention to my Raanaar Skeleton, and it ended up with one attribute point shy of what was needed to equip a bow... not that I'm even sure they can equip one, a crossbow didn't work, even though the skeleton had the stats for it.
Why can I equip arrows on the demon who can't use any kind of weapons?