Yes you can say ones each, when you use plurals. - Did you buy the children any sweets? - Yes, I bought them three blue ones each. Or when using the possessive, you can use each one's.. I've got three brothers and each one's wife speaks a different language.

"Ones each" doesn't exist as a phrase. If you find it in a sentence, they are in different phrases: "I love flowers, and I plant a few ones / each month." In your first sentence, remember that "one each" means "one, for each of them". Edit: just saw Mike's answer - yes, that makes sense! :) I initially did a search on the words "ones each" and mainly came up with examples like mine above.