"As much as possible" isn't very helpful if it's a small suburban lot; they'll have to pick and choose. Here's my advice from my own experience, in a one-acre clearing on a ridge in West Virginia, Zone 6B: some years I've had all the fruit needed for my two person household--this year I will have almost none, mostly, apparently because of a hard frost in April following some warm weather--it seemed hardly unprecedented to me but resulted in no redbud or viburnum bloom, which I never saw before, as well as almost no tree fruit--even though the apples bloomed after that frost! The tree fruit is more iffy than bush fruit in my experience, and don't forget most need pollination partners, although a neighbor's tree might provide that. Squirrels swipe most of my tree fruit before it's ripe anyway, except the apples--probably because the apples are later, when the hickories and acorns are kicking in.
Strawberries are right up there among the most reliable crops, and will produce plenty of fruit one year after planting. I grow only June bearing as they are reportedly more productive and I like having a season--after crawling along the beds harvesting every other day for a month, I'm ready for that season to be over--and I have lots in the freezer by then, as well as jam if I don't already have too much.Then the goumis kick in (except this year, because of that freeze--and the only thing I've found to do with them is make syrup, be cause of the pits, but that syrup thickened on a cheesecake under a chocolate ganache...and the goumis are pretty, fix nitrogen and need virtually no care. Then there are the wineberries, an invasive I have cultivated. And blueberries, I should have gotten serious about blueberries sooner as I have macular degeneration, AND it seems the one fruit my husband is likely to eat much of. Blueberries need little care IF you established them in a good bed to start with, which means two things_ VERY acid soil--the use of peat moss is the only way I've found--and screening out the birds. The best way to do that is to create a fence with one-inch-mesh chickenwire, six feet high. Then you only need to throw the netting over the top during the season, and snakes won't get caught in it. If you use T-posts, put a tennis ball on the top of each to avoid tearing the netting. I put mine on a hugelkultur. I have thornless blackberries but have had all kinds of problems with these. Currants and rhubarb seem to need a lot of shade here. The last berry is raspberries--I have a red everbearing raspberry, unfortunately I don't know the variety as I got my starts from a neighbor who doesn't pay attention to that--he bought them decades ago and mentioned that a farm partner said he paid too much for them. I don't know what he paid but she was wrong, as he got fruit from them for decades, mine have fruited heavily for over a decade, and I have given away quite a lot. They may produce a small harvest in June, on old canes, but the main harvest starts in August and goes till it frosts, in November these days. These are good for freezing, and jam. I also have two large wild persimmon trees that usually bear a lot of seedy fruit, and several grafted ones that produce bigger, nearly seedless fruit. And five apples, three peaches, four pears, some of them not bearing yet. That includes one standard apple I just planted last year--I was determined to get one in, in my lifetime, to pay back the unknown strangers who planted four big trees on my former land, from which we got many great harvests.