I always worry about trees with multiple grafts. I don't think they are as hardy as a single grafted tree (and pruning is a nightmare). I planted 2 or 3 separate trees in a single hole, spaced about a about 2 ft apart. They grow a single canopy, just like a fruit cocktail tree but each have their own trunk. Just choose trees compatible in size and growth habit. This is from a nursery local to my area:
Years ago my old mom had a multi apple — four, five varieties, perhaps? I don't recall that the tree ever got huge (dwarf maybe) but she got a variety of apples each year. Truthfully, it surprised me because I figured she'd fallen for a scam 😅
