Yep, sounds like an "all of the above" deal... As I rarely use the 3-pt hitch but use the MMM all summer long, I slid a piece of EMT in the BH mounts so the 3PH arms could be held out of the way, but far enough back that the hydraulic lift arms would also have clearance to go up & down as the MMM is raised & lowered. (3PH top link is removed.) Note that each time the MMM is moved, those hydraulic lift arms on the 3PH also move.
With those arms in the "normal" bungeed-up holes in the fenders, I found that the 3PH hydraulic arms could sometimes either hit the arms or possibly pinch a BH hydraulic hose. Bungeed to that EMT, they're safe (& quiet) but still out of the way.
cool connection -- I keep mine registered (in NH, as "construction equipment") so I can, when needed, legally drive it on the road. I have 2 locations that I've driven to in the past, each about 2 miles away.