A) 25ft+ nut (chestnut, heartnut, etc)
B) 16ft+ fruit (semi-dwarf fruit tree, pawpaw, hazelnut, etc)
C) 10ft+ small fruit (elderberry, goumi, jujube, medlar, columnar apple, dwarf fruit trees)
D) 5ft+ berry (currant, gooseberry, blueberry, etc)
E) 2ft+ herb (mint/thyme family, onion, comfrey, daikon, carrot/celery family)
F) 1ft Dutch Clover
Size of guild at maturity = A+ B/2 + C/2 + D/2 + E/2 = 25+8+5+1 = 39ft + (4ft walkway)
At establishment I plant alot of dutch clover, herbs, berries and then cull as the fruits/nuts require more space.
Dutch Clover for my nitrogen needs
Herbs to confuse pest, predatory insect habitat, onion family for bad soil nematodes, soil areation + mineral mining
Berries for a harvest next year
Small fruit for a harvest the 2nd year
Fruits for a harvest the 3rd year
Nuts for a harvest the 6th year
Dutch clover will provide most of the nitrogen as the food forest matures until it is shaded out.
Autumn olive/Seaberry at the small fruit layer with a harvest
I prefer Adler over locust. They are easier to prune, handle and remove and I can get 16ft+ cultivars or 25+ cultivars or 90ft+ cultivars.
Check out these guys for a list of all the nuts that you can grow in your zone 4.
You can grow most if not all the plants in the prunus subfamily, like apricot, sand cherry, etc.
You can grow pretty much every think in the apple/pear sub fsmily
Sadly no pawpaw for you though.
Most the berries will do fine in your zone 4/5.
When you have 50 different species, the odds of all or even 25% of them getting hit by pesr in any given year is tiny, but over a 20yr period every single one of them will get hit by pest. But on any given year you will be okay.