Refresh (replicate) MySQL database from server to server
I would imagine that a nightly "refresh" between two databases like you say would involve dumping one database and importing the dump into the other database. That would lead to major performance drags every time you do that process.

Personally, I don't think that is a great idea when there are tools that allow you to replicate data between database servers. I am afraid I don't entirely understand what your use case entails, but I would recommend reading up on MySQL Replication