Don't have a thread but can help. I converted my KRV 2000 to CNC not to long ago. I reused as much of the leadscrew mounting bits as I could and it went quickly.

You have an older bridgeport model that does not have central oiling and that is one thing I would consider essential for the health of the ballscrews at least.

My first suggestion is think of a budget of at least £1500-2000 for the conversion if you want a professional quality machine.

The donut motors should run fine on the inverter (VFD) if you get one that is rated to the HP of the motor.