The REST API was originally designed for Data Management in EPM Cloud, so the emphasis was on PBCS and FCCS.
This was then pushed down to on-premise, the issue I think you will have with HFM is that not all the export options are available.
we are going to use Replace only.
So that will do right?
What is typically needed from client side to be prepared?
Yes, it should be ok, you will need to decide how you are going to call the REST API.