I think it would be ok to house the baby zebs in a 10g, I've got 18 in one 10g now. Stack some rocks (no gravel) for several caves and crevices (did I spell that right?) and they seem to stick to one spot - I think they like each other at this size

- the wee ones, that is. The older ones are starting to move around a bit more. I added 7 new fry and made small crevices for them and they still hang out where they bigger ones are. The small are under and inch and the older are pushing 2 inches, maybe larger.
I would have to agree to keeping fry separated to species. Just for food, because one might be less shy, thus leaving the shy hungry.
But as the saying goes, what works for me may not be what works for you... Kind of what is trash to someone is treasure to another, or poison or some other saying... I ramble,so er... Merry Christmas!!