‘Adara’ plum (a clonal type of Myrobalan plum: Prunus cerasifera) is your stone fruit answer. You buy something like Marianna 2624 and krymsk 1 and graft ‘Adara’ to it.
Choose your rootstock (it doesn’t have to be Marianna 2624 or krymsk 1 but when you figure that out) and plant them to get rooted in well, & then you’ll graft after a year of growing/establishment. You’ll graft ‘Adara’ on what you choose as your rootstock of choice for your soil type. Then, you’ll graft cherries, plums, peaches, nectarines, Asian plums, and everything else you wish to graft onto the ‘Adara’. I don’t want to overwhelm you so I’ll stop here. This is to information about Adara/Puente.
You’ll need pawpaw seedlings in place to graft onto: Asimina triloba
You really should plant at least one American persimmon or a hybrid such as JT-02. JT-02 is basically a hardy ‘Hachiya’. ‘Prok’, an _American persimmon is always an easy go to recommendation for an American persimmon because it’s early, when orange in color and still a bit firm has lost its’ astringency & when it ripens further it’s even better, & it’s very large. Neither JT-02 nor Prok need pollination and alone or as a pair will produce seedless fruit.
You want to graft and do this, then it’s always best to plant your rootstocks whether clonal or seedling form & wait at least a year and then do your own grafting onto them. But, you need them to become established. Purchase 1/4" seedlings or clonal rootstocks. They’re the best size for the fastest establishment. If you can’t get 1/4" then get 3/16th’s. Don’t buy anything larger.
The only issue with your plan is you have 5,000 sq. ft. when you need 10,000 to do what you want to do, correct. The guy that started that started this group and not to exclude @mroot for his suggestions about tall spindles either, @scottfsmith has trees planted in these incredible tight spaces you’re talking of. You’ll now see that Scott’s trees are leafless from below about 6’ or “whatever” and that his trees have taken on “odd shapes” due to jam-packing. To grow fruit trees like this you must be a master pruner. You need to know how to keep a tree from getting out of control and not cutting off next year’s fruiting buds. A master pruner. One that knows how to prune Spring, Summer, and late-winter/Early spring to keep this marvel of a close planting proximity in full check. In case you didn’t know in a matter of 2-weeks time, a peach tree after it’s several years old might grow 4’ in all directions during summer… so there are a lot of things such as these to consider when you’re talking about 5 feet between trees.
This is Scott’s orchard or a part of:
from this post:
Sincerest gardening regards,
P.s. ‘Adara’ aka ‘Puente’ is only necessary when your stone fruit rootstock of choice won’t be compatible with something. Maybe you want to grow a cherry tree but you have a plum rootstock. That’s where ‘Adara’ performs its’ magic.