I was appalled at the second post in this session and really enjoyed how you handled it. I also am not a fond believer in the grey market tractors and I have a reasonable mechanical appitude, but that is another story.
I am sure you will find that people aren't going to want to come over and do the rough work, and leave the easy stuff for you to finish, but they will do what you pay them to do. If your brother's tractor is available, I would purchase a medium size bush hog in a midium grade of durability. Sometimes an old heavy duty bush hog is better than a brand new light duty one, and may cost almost as much. A heavy duty or at least a medium duty one will last you a lifetime if you can keep it maintained and out of the weather. Covering it with a tarp in this state just invites rust so consider somewhere to keep it under cover if possible. A few shots of grease before use and a quick cleaning after will make a lot of difference. A stump jumper is probably a requirement. They are a round blade holder that looks like a frying pan with wings. (Wings being the blades). The stump jumper allows you to hit stuff and have the center shaft ride up over them instead of hitting it and having something break. The blades are designed to fold up when you hit something and although they might make a lot of racket doing it, they generally don't harm the bush hog. I had a Ford 1100 4x4 that I put through things that you wouldn't believe. Some of it I still don't believe.
A bush hog will cut grass but it doesn't give it the manicured look that a finish mower does. A finish mower won't cut brush worth a durn so I think you might be better off with a good bush hog. Sharpening the blades and running a little slower with a bush hog and you will get a better cut later when you have the rough stuff done. For the rough stuff, the blades don't usually get sharpened, at least not till they are pretty dull and then only to knock off the rough edges. I noticed you said your property was sugar sand, which is typical for a lot of this state, but for some reason I keep thinking that that area has a lot of blacker dirt with a high sand content. Maybe I am wrong, been a while since I ran down that way and my memory gets to acting up from time to time.
A tiller in my opinion is a waste of money. You don't care what your land looks like under the grass and if you start tilling it up, your going to do two things. One is dig up a bunch of roots that are better left buried and two your going to tear up somebody's tiller. It takes a reasonable amount of horsepower to turn a tiller thru roots and that horsepower is going to tear up the tiller. If you just got to move some dirt, a box blade with rippers will do more for you than your ever going to get done with a tiller. Plus it will make spreading that dirt fun! It will actually make you wish you had ordered twice as many loads of dirt.(Side note to the dirt purchase: Don't let them dump it in a pile. Get them to dump a single load as they are pulling forward and put the next one somewhere away from it). If the ground need breaking up, get someone to come pull a set of disc's around rather than a tiller.
I wish you luck with your endeavor and hope you realize that there are not any stupid questions. Ask anything you want to know the answer to and we will try to answer it to the best of our ability with the information that your able to offer.
I think a look at your brother's tractor to see what model it is would be very smart at this time, before attempting to purchase something either too big or too small for it. If he knows the horsepower, that might also help if you don't have the model number.
David from jax