Is it possible to have MRP generate the Work Orders, rather than a planned work order?

No, you need to generate the work orders from Planned Work orders. The reason for Planned work orders is to allow the supply planners to review the WOs before committing.

I'd double check the Manufacturing Preference > Create Work Orders in Supply Planning. This may have been the old supply planning but I'm not sure if this impacts the Planning Workbench. However, it sounds like a disaster depending on your planning horizon

If I am understanding the question - yes this is possible with a Suitelet. Once the WO is created by the Suitelet (can be bulk operation as well) the Planned Work Order is cleared after re-running the repository. Problem Solved.