I agree 100%, these 250's wheelie easily, be careful if your planning on a passenger, I should imagine it will cause havoc if you attempt a relatively steep incline.
You want foot pegs for the person on the rear seat? Or just footpegs? I used folding pegs for a sailboat mast, the black version of these:
https://www.ebay.com/sch/i.html?_od...&_nkw=sailboat+mast+folding+footpegs&_sacat=0
I made a fiberglass panel along the rear fenders, using the fenders as the mold (12 layers, 2" wide) and then bolted the folding pegs to this when it was cured. Gives a lot of stability to the rear rider. Handles were 1" rounds, but I would use larger next time - 1 1/2".
Riding is much more stable if the rear weight is inside the rear axle, and grossly unstable if it is not. Rear rack is designed for 120 lbs, but not a rear rider. Any bump, even at 10-15 mph can flip you back, and quickly.