What is your budget? Do you plan to keep it or sell it when you are done? How good are you, or should I say, how willing are you to wrench on it?
Small dozers take a lot of time to push out stumps. They also have to remove a lot of material to get the stump loose enough to come out. You burn a lot of fuel using a dozer to remove stumps.
Low priced dozers are well worn. Parts and lots of tools are needed to keep them running.
Of the three brands you listed, I think Deere is going to give you the best bang for your buck. Cat is a better machine, but parts can be pricey and the machine will cost more then any other with the same HP. Case does not support older equipment very well. It will be the cheapest HP out of the three, but if you can't find a part for it, then it's not doing anything for you. Deere makes a good machine and they are better about parts then Case.
If you just want to get stumps out and you have no other use for the machine afterword's, an excavator is going to do it faster and easier. When you are done, it will be a lot easier to sell compared to a dozer.
I own a Case 1550 dozer. It's 170 hp and weighs 40,000 pounds. I also own a New Holland 555E 2wd loader backhoe that's 80 hp. The backhoe will take out stumps night and day faster then my dozer will. And after the stump is out, I can fill in the hole created by the backhoe a lot faster then what I created digging out a stump with my dozer. But this is in hard packed red clay.
Sand would be totally different. Root structure also makes a huge difference. Some trees pop out like they want to come out, others will hold on like they are held in with concrete and super glue. Given how different our soils are, what I say probably wont apply, but then again, stumps are very tough to get out and I would still want something to dig them out instead of trying to push them out.