Both of these weapons are known for summoning Skeletons when you kill an enemy. My suggestion is that instead of giving them strict time limits (10 seconds for Burning Skeletons and 15 for the Bone Harvesters), can you give them infinite time limit, but have their health drain quickly so that they only last 10 seconds if you don’t have great minion regen?
Not only will it give minion regen a very useful stat to look for, but if allows you to carefully manage an army of exendable minions that would be build-defining for multiple builds. Primalist doesn’t have many fire abilities, so I don’t see this suggestion get broken with Beastmaster, but it would open up multiple other types of minion builds.
As it is, you can only get 2-3 Skeletons if you’re lucky before they disappear, and the time limit means that there’s no use spending any healing on them. Hopefully you’ll consider changing the pets to make these weapons truly build-defining.