Is there still going to be an option to post just to the BCH chain?
It was nice to have unsplit transactions at first, but I feel like it may be better to separate them at this point
If you turn off split protection in settings it won't pay attention to which chain coins are on.
In theory, but big memos sometimes get confirmed on BCH. Transactions are broadcast to both chains but miners are pulling transactions from both mempools anyways.