I believe Montague and I covered your stamina training for wrestling fairly well in the recent past, so that should not be a major concern for you. As far as MMA goes (which ever version you are experimenting with) you have already learned the basic take downs, leverage points/hips, holds, etc from wrestling. You do want to improve the grip, which a lot of guy's overlook. Might try sandbag training (do search for a training program) as a start. Excellent grip/forearm and stamina workouts. Can get sandbags at any fire/ranger station out here ( SoCal) for free. I am sure where you live also.
Lot of striking drill around, with or without a heavy bag. Maybe more important is to work on your defense and blocking of blows. This also is in regard to the knee's and feet. Straight, side or roundhouse kicks are also great for endurance and flexibility. Timing and quickness is going to be a major factor with any style MMA you may choose.
If you want a weight exercise for stamina (endurance + strength) that do high rep sets of the clean and jerk and the SLDL for a start. Can also throw in squat cleans for those higher reps (nothing less that 20 reps per set). If anyone wants to check out how out of shape they might be, than try a few of these exercises. You will find out right away. Good Luck.
