spindle motor upgrade

I have a Bridgeport V2XT currently 3 hp intermittent and 2 hp continuous spindle. Got it running on a Mitsubishi FR-720S-100 VFD. Interested in replacing that spindle motor with a 3.7 KW and then having to change the VFD to a bigger Yaskawa so can continue running on single phase or maybe I just keep it 2.2Kw and enjoy the greater speed range? That's my first question, is it worth the trouble of trying to figure out how to mount that bigger motor getting bigger VFD new wire brake etc etc or just sticking with the same HP range?

Now the motor in question is a 145BGL-M3P715/240, that is the 3.7 Kw model. 24,000 rpm max rated to 12 amps ( My VFD rated for 10 amps maybe that will suffice?) 240VAC motor. The 2.2Kw model is 145BGL-M2P215/240 Amps 7.1. Wish I can attach the PDF that the salesman sent me. Now my 2nd question is and I have badgered the salesman and hope he knows what he is talking about, whether this is a servo or asynchronous motor that can run on VFD. He says it will run on VFD. Will this thing run on a VFD? 3rd question is about the encoder. I would like to maintain the backgear set up on my machine so I can get higher torque on those lower RPM's. The motor has a motor mounted encoder. I am running mach 4, plan on running the encoder to the motion controller Apollo III which is Hiconn 7752. Does anyone know if there is a way to have ratios so that the encoder counts are reduced by 8.9:1 when the machine is in backgear. The motor already comes with an encoder so why not just use it, would be easier to put the encoder on the spindle. Can the encoder be fed to VFD?

Bottom line, my questions are
1.) will this rotor work with a VFD like the salesman says?
2.) should I go with 2.2Kw or 3.7Kw ( need new VFD cable, brake and who knows what else)
3.) what do I do about the encoder? Is it better to find a motor without an encoder?
4.) Is there a better way to go about this?
5.) Are those motors any good? Is there a better option?