Will this motor work for a consew 225?

yes, the motor will retrofit into the standard slot dimensions. very easy to align and adjust belt tension

Will this work on a consew cp206rl

This motor is for non programmable machines (i.e. back tack). If you just need a motor to drive the machine, this will work. It is plug and play 110v and very quiet. Adjustable to your drive belt and comes with everything to mount to the table.

Will this work on a consew 220 sewing machine? And will it slow down enough to get down to a very low speed of 50 stitches per minute?

It will fit very easily into the standard motor slots and is quite easy to adjust alignment and belt tension. The motor will run as slow as 500 rpm up to 3500 rpm. The servos have much more control than the old style clutch type motor. You can also by an add on that will allow you to sew one stitch per step.