Only the larval stage of a shrimp(along with other crustaceans) is called a zoea(or nauplius depending on the stage of development). Since most of the shrimp we keep give birth to fully formed benthic young, the word shrimplet was coined to describe them. I suppose the correct way to say it would be juvenile, but I think shrimplet is cuter.
I think the deed may be done. Looking at the big moma shrimp last night, it seemed to have lost the shrimplets/zoes/shrimplings. No sign of them but with any luck, they'll show up soon.