Older figures open fine, at least back to A3, which I use all the time.

For Genesis, there is amorphs package, but the current focus is the Genesis 2 line, so I would consider that. (v6/M6 version 6 stuff)  I don't personally use the V6 stuff, but since it released, the Genesis line gets very little attention by vendors...

For V4 face morphs to use on a genesis character you can either remake them, or buy the GenX product, and my guess is we will get a Mayhem sale again soon, and you should be able to pick it up 1/2 price, by adding a few free items to your cart as well.