The WWs were more infested by mites than the other? Hm. They do pierce the plant's leaves and suck juices... it would certainly be a shock. But I don't know enough about the scale of damage on different levels of infestation to make a statement on that, lol!

Put the ladybugs right on the soil surface and they will be happier. They can flip themselves upside right more easily on a rough surface. The neem should not be harmful to them; I'm not sure though how toxic pyr residue is to ladybugs after a week. They are still alive, anyway... that's a start.