I agree with Jeff and second the decision on an excavator for stumps. It sounds like you could use around a 5-10 ton machine. The bigger the quicker it will pull up stumps. If you have the room for it, a 20 ton will pull them out in seconds. It is all about weight and counterbalance...these huge machines have all you need. If you dont have room for it, then a smaller mini-ex at around 5-10 tons would get the job done. If it is really tight you might get by with a skid steer and a tree stumper, but they take a bit to get used to as well.
For tractors Jeff has you set. You need weight for moving dirt/plowing. You need HP for a mower. Do you need/want a cab?
I would say somewhere around the Kubota L series size. Other brands include Deere, Mahindra, RK, LS, Kioti, New Holland (its an LS), Massey Ferguson, Branson...and I probably missed a few. As Jeff mentioned find a good dealer that has in house service and longstanding business.