Thx for posting the Bush Hog subframe pix. It looks like you
have to completely remove the 3-pt arms to install the backhoe. Inconvenient, to say the least. I have seen this
with Woods factory subframes for Kubotas, too. When I
build the subframes myself, I try to avoid any use of or interference with the 3-pt mounting areas.
As for being able to use the Bush Hog subframe with other hoes, unfortunately there are a variety of different hoe-side
mounting areas.