Farmer, I'll offer a few general comments with regard to the peach. Most people don't prune their peach trees at all, or wait too long and then want to correct. After this it can be pretty tough sometimes, though not always impossible, to bring it back to the shape or size desired. Perhaps an analogy would be building a house. If the foundation received little attention, it's difficult to rectify a problem, if the rest of the house is already on top. The good news is your tree is still small enough you can train it any way you like. If it were my tree, I'd select three scaffolds, going in different directions and cut everything else off. Ideal scaffolds point more horizontal than vertical, are spaced uniformly around the trunk, and are separated by about 4" vertically on the trunk. This is going to get a bit complicated, but I'll try to give you some specific advice about your peach tree. It's hard to tell from pictures, but on your peach tree it looks like you could select the big scaffold lowest down (pointing towards the right) for your first scaffold. Take a tree saw and cut the scaffold from the underside about 1/2" away from the collar. Cut about 60% through the branch with your tree saw (again from the underside). Move up the branch and inch and repeat (cut 60% through the branch from the underside). Move up the branch another inch and do it again for a third time. Now that branch will easily bend down. Bend it down about 30 degrees from horizontal and tie it there with some string (make sure you tie a large loop, not a tight loop, around the branch so you don't girdle it). Don't pull so hard you break the branch off. Tie the string to something which will hold the branch at that angle. I strong piece of wire pushed in the ground makes a nice anchor, or a large rock, or a jug of water, anything. The branch cuts you made with the tree saw will heal over and the branch will be set more horizontal. Because of the cuts, the branch will grow a little slower, which is a good thing in this case because it's currently too dominant. Next there is a thin low branch pointing toward the left. Leave it. It should make a nice scaffold the way it's going. It is a bit too close to your first scaffold on the trunk, but these things happen. Lastly, go up the tree a little more and pick a scaffold pointing away from the camera. I can't tell where on the trunk that occurs, but I do see some shoots pointing that way. You'll need to tie one of those shoots down. They look small enough you won't have to use the tree saw. Again tie it down about 30 degrees from horizontal. Cut everything else off. As your peach tree grows, keep pruning the strong vigorous vertical (upright) growth and leave the more horizontal growth. As you get more growth on the three scaffolds you selected, don't be afraid to keep tying things down if you want. You can always prune upright growth off, but you can tie it down too, if you are short of more horizontal growth. Either way, just don't allow that strong vigorous upward growth. It isn't the most fruitful wood, and it gets your tree too tall. Lastly, it would be a good idea to put about a 4' ring of mulch around that tree. Young peach trees don't compete well with grass.

Welcome! You have chosen a hobby that can that can feed body and soul for a lifetime! Avocados sound like a difficult choice to me but I haven't tried myself. Have grown most of the others mentioned in pots. They all bear but don't expect enough to cut your food bill noticeably. Groworganic is a good supplier. I bought 10 of their trees last yr. Price is right and all grew but they were minimally packed and kinda dry on arrival. I'd suggest looking for bare root trees in January at big local nurseries. When I lived near Fresno they carried them at good prices and at the best planting time, mid winter. My favorite low chill nectarines that should be widely available bare root are Arctic Star and Snow Queen. Check out the San Diego chapter of California Rare Fruit Growers online or whatever chapter is nearby. They have long lists of best cultivars, scion exchanges, and regular meetings to learn and meet fellow growers.

Apples survive a tremendous amount of wood removal if they're healthy to begin with- plums not so much. I've lost track of how many old neglected apple trees I've remodeled but when I started doing this professionally I read Hall-Bayer's "Ecological Fruit Production in the North" which has a very easy to understand chapter on getting overgrown apple trees back into production. After spending half my work days pruning mostly apple trees for the last 20 years I've developed my own systems, of course, but a lot of the trees I face could be quite adequately managed using the photos and explanations in this book. If the plums are Japanese you can go after them more aggressively then Europeans. Yes, you can usually get away with removing the largest scaffolds on any healthy tree, depending, I guess, on local insect and disease pressure. Here in southeastern NY I don't believe I've ever had trees die from wounds I've inflicted on them and I remove whatever I have to to bring trees down in height. I just don't do it all at once.

I had several Apple, a couple Cherry, Plum, and Crabapple trees at my previous house. I used to prune all the fruits trees in February or March, if the snow wasn't too deep. The Sunset "Pruning Handbook", which I purchased over 20 years ago, says this about Apple trees: "The time to prune apple trees is in late winter or very early Spring before new growth starts."