It all depends on how many things are visible at a time.
You'd probably have to do some optimizations to disable the animated sprites as they go off screen, but apart from that, performance wise, the number of images in a sprite collection (spritesheet) doesn't really matter at all. 10 different units from 10 different sprite collections = 10 draw calls roughly.
A couple of things to keep in mind.
Make sure your sprites of different spritesheets are in different z values. Group sprites from the same spritesheets with the same z, so they all sort at the same point. Ultimately this means 1 draw call per "layer". If you mix everything up, you'll end up with an uncertain number of draw calls which is something you really want to avoid when you have that many active sprites.
Try your best to group all assets for one unit in one spritesheet - again you want to try to minimise draw calls, as otherwise you'll find it increases massively.
Depending on the amount of overdraw, you should be able to hit 60 (obviously this depends very much on your script code too), but in terms of GPU overhead it isn't massive.