I'd be looking at what machine you need longer term, and maybe buying that. Do what it can do during the setup, and either rent or hire out what it can't do. Otherwise you'll need to buy a too big machine (or wrong machine), then sell/rebuy. Not that it matters that much, tractors don't lose much value.
For some of your setup work a tractor isn't really the right machine. Do you have appetite to buy an older (but big) machine - bulldozer or excavator - until some of the work is done, then sell it?
Sounds like you want a cab tractor? If so, Grand L or M. MX I think doesn't have a factory cab, or at least not a good one? If you want a front snow blower, then Grand L is the right machine. If that's not essential (and you can move snow with a bucket, with a plow truck, with a rear blade, or with a rear blower) then M is an option.
In terms of your jobs:
- Cutting down trees. If someone will cut them and take away the timber, that's great. Otherwise, the actual cutting is a chainsaw, the question is what you're doing once it's cut. If it's a massive pile of firewood, then you need a splitter. Make sure you get rear remotes to run one. If you're trying to get lumber out of it, then you need a sawmill or a guy with a sawmill (probably the latter, they're not super easy to use I gather).
- Cleaning up after cutting down trees. Lots of branches and trash. A grapple is essential, therefore also a third function. Assume you'll make a huge burn pile and just burn it, anything else is too much work
- Stumps need good thought. What are you really doing with them? Grinding them means you're leaving most of it in the ground, they'll rot over time and the ground will subside, and it'll annoy you. You'll be constantly filling/levelling, or driving over holes and mounds. I think it's a better investment to take them out. A TLB is not really the tool for that job - it'll do it in a month of Sundays (as in, 30 Sundays, so half a year or more of work every Sunday). A big excavator will do it in a couple days. But then what - now you have holes all over your property, and a big pile of stumps to burn? A big bulldozer will flatten that again, but your topsoil will all no longer be on top.....and you don't want to bring in soil for 20 acres. Make sure you know the plan for what you're doing with the stumps, I doubt your tractor is really doing it
- Digging ponds can be done (slowly) with a TLB. Putting in a driveway can be done slowly with a bucket. Home foundations can be dug with a TLB. Septic can be installed with a TLB. To be honest, you're spending good money building a nice house, you're not living on the bones of your ass. A professional will do all those jobs way better than you ever will, and the guy plus his machine will cost less than your time/fuel/wear and tear. And the foundations will be straight and level, the driveway will have nice drainage, crowning and fall lines that you'll be pleased with but couldn't do yourself (or wouldn't even know to do), the septic will last a lifetime instead of giving you constant problems because you got something not quite right. I love doing jobs myself, but I'd personally limit myself to installing the pole barns and the like that I'm the only one who uses, and leave the house, septic and driveway (i.e. the bits my spouse uses) to professionals.
- If that's what you're doing, then your tractor is really a farm tractor plus snowblower. Grand-L, perhaps with a backhoe for smaller jobs, would be a great machine for that. Get the snowblower, some rear remotes so you can run a wood splitter and top+tilt for driveway maintenance, 3rd function and a grapple. Get the factory cab. Get a land plane for driveway maintenance. Make the yard bit of your house a couple of acres, and use your tractor to make it very level and lay a beautiful lawn with curves that the tractor can run around. Get a RFM and mow it fast. Get a rotary cutter for keeping the fields down. You'll be super happy.