No reason at all you can't run it from a power beyond if your pump has adequate flow. Our NH Tn75 has about the same flow as my Bobcat 773 so it could run the same blower (provided it pressure spec is simular, I don't know that spec off hand) However it is the first tractor we have owned with 17 gpm flow. Even better would be if you could combine the flow of original pump with a pto pump, a "tractor hi flow" which is how it is done with a skidsteer when you really want the snow to fly.
Also the 773 with 16.9gpm at 3000 psi only gives you about 27 hp. (plus there is a 25 gpm hi flow option with the turbo motor) Not bad for a 46 hp machine, but it might seem a bit low for a 75 hp tractor. I don't think any of the hydraulic blowers would be abe to match the shear brute hp that a pto blower would have. You will likely need more patience with any hyd blower.
The tractor would also need a wider blower to clean a path for the tires then a skidsteer. So it would be better if it had a hyd hp advantage. At any rate the more oil you can pump the better.
Ken