Some folks will say you need the 1725 rpm motor because it has more torque at lower RPMs, but you don't use much torque at lower RPMs where you're normally using a finer grit belt. I when with a 3600 rpm motor due to cost. With an Ironhorse motor (most cost effective) a 2 hp, 3 ph in 3600 rpm is $165 shipped while the 1800 rpm is $222 shipped.
Look at it this way, you want at least 4,000 to 5,000 SFPM belt speed at max for hogging with ceramic belts (I use 4100 SFPM), and you really need to be able to turn down to around 300 SFPM for slow fine "touching". Yes, that's a tad more than the usual spec'd 10:1 turn down but it's doable (I run 300 to 4100).
With an 1800 RPM motor you'll normally run max of 120 hz to get 3600 rpm along with a 5" drive wheel to get around 4700 SFPM belt speeds. Works just fine. You can also use a 3600 rpm motor with a 5" drive wheel for the same speeds. Yes, it's true at 50% speed you'll have full 2 hp with full torque with the 1800 rpm motor, but you won't be using anywhere near the full amount, more like less than 1/2 and you'll have more than half with a 3600 rpm motor. So, you've only gained something that'll never be used.
Either motor will work just fine and you'll never know the difference in use. One thing, the 1800 RPM motor will have full cooling at 50% speed while the 3600 rpm motor will only have 50% cooling, but that's still more than really needed since it's not got much load applied, and it's not running 24/7 as spec'd in industry.
single phase isn't even in consideration since you can't reasonably use a VFD for speed control.
forgot the link to Ironhorse motors.
https://tinyurl.com/spbwf4r