Sorry, just to be clear - you are towing a FWD Sportage w/dolly on front wheels, but they are saying it needs a rear wheel dolly, too? All because the Sportage somehow senses movement in the rear wheels when it is “off” and pops the parking brake on?
Is there maybe a fuse that can be removed temporarily that is powering whatever this sensor is?
Something is off here. The manual specifically states that FWD can be towed w/front wheels off ground. Is there any chance that Auto Hold was on when you powered off the Sportage, as that would do it.