I am not sure what you mean by the DEF flow. If, by that, you mean a flow that reads a DEF file, then reading a DEF does not require anything beyond RC200. However, other licenses may be required if you want to enable physical features such as congestion mitigation, etc.
As per the DEF, indeed a floorplan is what is expected and recommended and not a detailed floorplan. If you have a final floorplan, all cells are fixed and hence there would not be much for the synthesis tool to do
Please review user guide