The JD-650 has a front mounted PTO to courses backward to the mower gear box. The mower suspension is also quite different, but maybe adaptable (if you can weld/fabricate what is not possible?). If you turn the gear box 180 degrees you "might" be able to modify the drive shaft to fit the Kubota. I have never had a snow blower, but the 650 front mount PTO does connect to it from the front of the tractor, you would certainly have to do some creative mods.
I have handled 36" heavy wet snows with my rear blade using tire chains all around and ballasted tires. Worked amazingly well, but speed certainly was not impressive as I backed the snow over the banks in short swaths. We rarely get such snows here in southern WV, but 1976, 1977, maybe 1984, and last year we did. Last year I did not have the blade on no way to get through the snow to get to it -- this year it will be on, hope to see not such snow here ever again (wishful thinking, I suppose). The shale/clay ground here is so hard that worms have evolved hard harts and jack hammers to make way ;-) I forgot to mention that the 650 handles a 48" rear rototiller with the greatest of ease, but that is a slow process inherently.
prs