Just to get the definitions straight so we are all talking the same things here.
A SUB-CUT is a super small compact utility tractor, it is what the JD2210 and Kubota BX series tractors would be considered. Generally they have about 22 ot 24 hp and they have MINIMAL ground clearance.
A CUT is a compact utility tractor. They are divided into roughly different sizes or classes. New Holland calls them CLASS 1, CLASS 2 or CLASS 3. Many people refer to Class 1 as a "small frame CUT.
The TC24, Kubota
B7610, JD 4115, JD790 and Kioti CK20 are all "small frame" CUTS.
All of these will have adequate loaders for what you want to do, but the NH loader is probably the best, the CK20 loader is right there too, followed by the JD and the Kubota. But even the Kubota will move large piles (read that as a pile the size of a hill) from point "a" to point "b". From the perspective of "FEL" or Front End Loader work, I would say the TC24 is going to be the best choice.
For mowing with a Mid-Mount Mower, the Kioti will lag behind the group as it has lower available hp and the mower is reported to be undergoing some redesign to correct some performance issues. All will handle a 60" MMM but I don't think any will handle a 72" mower deck unless you have really sparce grass and live in a very arrid or very cold climate where grass is not an issue. As you said that mowing a prime concern, I would say the Kubota will be your best choice, it offers more HP per pound of gross weight than any of the other tractors, the CK20 will be on the other end of the scale offering the most weight and least HP available to the mower deck. For grass, weight is an issue, as soil compaction and rutting come into play. No question the Kubota will be the best mower. Make sure you can "pin up" the MMM deck, so you can do other work while leaving the MMM deck on the tractor. "Pinning up" a deck takes less 1 minute and keeps the deck from dropping when the 3pt hitch is used; virtually all modern decks come standard with a couple pins to do this. But when doing rough work, you'll still want to remove the deck so make sure it removes easily. (I will never give up my MMM now that I switched to one from a RFM). I honestly don't know if the JD790 will operate a MMM, but if it does, then I believe it has a bit more HP than the other models so it might be able to handle a 72" mower.
For box blading you have a traction issue. There weight & power are your friends. I honestly don't know what is better, power or weight, but both are important, weight is probably slightly more important. As the TC24 offers both weight and power, I would say it is probably the best overall choice, but the CK20 offers 300# more weight than the TC, while offering 12.5% less HP for pulling. The JD4115 would fall in line next, followed by the Kubota. But the JD790 might be the best of all the machines.
As for snow removal, that is a toss up. If you buy a snow blower you have multiple choices. The JD4115, NH TC and Kubota B all offer front snowblowers, those are excellent. I doubt you can get a front blower for the JD790 or the CK. For 1/2 the price of a front snow blower, you can get a rear 3pt blower, and there all 4 brands will power a rear blower, the CK being the least capable only because it has lower availble PTO hp. Now you have 2 other choices for snow removal, using a simple rear blade, typically turned backwards and run in reverse or you can use the FEL. All 4 will be equal with FEL snow removal unless you get hit with the mother of all snow storms, then, and only then, the Kubota might maybe lag behind a bit, but maybe not. With rear blade snow removal, weight is your friend, but for any snow that is going to be under 6" I don't think you'd find any real or practical advantage with any of the tractors.
As for smoothing your soil, yes a box blade with scarifier teeth will smooth the yard, but you will make a big mess of it before you get it smooth so be prepared to practice.
As for price, I suspect the only two that I think you can get new for $15,000 would be the 21hp CK20 and possibly the 24hp
B7610.
