They say that the Voxel Free and Voxel Pro doesn’t support UE’s Procedural Foliage system. this isn’t True!
you need to make a few additional steps to have it working. and yes, it will also work alongside of the Voxel foliage placement system.
Why would you have 2 Procedural Foliage systems running at the same time? Simple the Voxel Pro Procedural lack the Clustering that the UE Procedural can do.