You would be safe with a 1200 oz/in NEMA 34 stepper. Operate them at near the maximum voltage that the drive will handle. That should give you 500 IPM rapids and plenty of torque for cutting. I had a similar system on my router that was a lot heavier than yours with a 1.5:1 belt reduction. Moved the Y at 0.75 inches per motor rotation.
For steppers, I like the Automation Direct steppers & drives. Not cheap, but they work well. https://www.automationdirect.com/adc...tepper_systems
You might look at the ClearPath servos, I have had good luck with them. https://www.teknic.com/products/clea...-servo-motors/
or the DMM servos, I use those also. DMM | AC SERVO DRIVE | AC SERVO MOTOR | ROTARY ENCODER