In short, I think making a Chaos army from these figures is going to be a little bit challenging. In long...
Made a start this morning. I've got one pack of Erynies, 20 figures that I'm splitting to make 2 units of Harpies.
Man but they are fragile! Be VERY careful, or you might break the figures from the small base they are on. It hasn't happened to me but more by luck than judgement I think! I don't know if the Erynies are suitable for gaming with, being so fragile, I can see them breaking in the heat and excitement of a game if you're a touch on the ham-fisted side. Fortunately I'm "just" a collector, so it shouldn't matter to me. Gamers beware though!!
As the bases are so small, I've stuck them to the 20x40 base by placing a large drop of super glue on the base, placing the figure into the glue, then quickly dropping fine sand around the figure base. All the while holding the figure, as they tend not to stand up on their own -
especially the flying one!!

If the infantry figures are the same, I'll be using a lot of sand and glue to fix them onto the bases - and I've got 8 infantry units to make up. Fortunately the cavalry, chariots and young drakes look to be OK for basing, another 8 units.
Anyhoo, my finger tips currently have bits of glue/sand on them, but at least I've got one unit on the bases. Painting next...