Some specimens don't make it through the bare-rooting process in very good shape, none appreciate it much but this may be more of a problem with stone fruits than those like apple and pear trees. Bare-rooted stock is basically big cuttings that have to re-grow their feeder roots before the top can grow normally again, the first summer after planting the top is dwarfed. New roots come out of the cut root ends in spring, after the overwintering buds on the branch ends open. But these don't grow long enough to restore the vigor of the top growth. That happens after the new set of dormant terminal buds at the ends of the branches is set in fall - at which time 60% of root elongation for the whole year also occurs. If your apricot does not bud out and produce leaves then there is definitely a more serious problem than normal. Especially if it came out of bins at a local outlet somebody may have let it dry out, around here shoppers often pull out the one the want and leave any others that may have come with it sitting out on the path or floor.

You do not need to be above the tree to prune. You could have a branch that is 10' tall and cut it at 4'. You certainly wouldn't need to get on a ladder to make the 4' cut just because the branch is 10'. All the trees you mention except for the cherry, which you will probably kill doing what you want because they don't handle constant or heavy pruning well (and it sounds like you are going to cut a large central leader to make an open vase, which is why my old cherry tree split about 15 years after I had that idea), and the guava (which I just don't know about) fruit on last year's wood. Once you get your basic tree structure down your pruning will be replacing old branches when they get too big and heading back new branches to encourage fruiting and strength. You can bend the branches down to do the heading back and the branch replacement will be done at whatever level you decide your fruiting branches will come from. That level could be radiating from a central leader or it could be a system of scaffolds. I see a lot of overgrown "new wood" fruit trees and the reason is people didn't train them with the idea of branch replacement and to continue getting fruit they need to let the tree continue to get larger and larger. Let's say you decide your base will be cut at 4' and you will allow the trees to go no more than 10'. If the trees grow 12" a year or you head them back so they grow no more than 12" a year that means you will be replacing branches every 6 years. I don't know about zone 9 but 6 years is not a unmanageable branch. If it is you could decide to replace every 4 or 5 year branch and have an 8'-9' tree. If you are really stuck on having your trees only be 6' (which like I said above, there is no pruning reason to have to have them at head height to prune them since you will be removing well below the final height and can bend whips down to head them back) you would be cutting them off after every 2nd year. I'm not sure your trees would go for that, they may decide they don't have enough tree compared to root to bother trying to populate and growing tree is more important. I have a McIntosh that hates being espaliered to 5' and it's always trying to grow more tree instead of getting heavy with fruit. You may have to do some root pruning to make them satisfied with 6' of tree or do some other stress/extra dwarfing techniques to cause them to bear heavy so they don't have the energy to make more tree.

my meyer was 3' tall when i bought it a few years ago the first two years it had about 10-12 fruit, as they fruit got bigger and started weighing down the branches, and then the trunk started to bend towards one side, that's when i thinned out some of the fruit. i kept the green lemons and used them to flavor my ice water and iced tea. your tree is limber, but if you feel there's too many fruits on one branch and its bending more then you feel comfortable with, feel free to pick a few to lighten the load. as far as whether your tree has enough energy to support that many fruit, don't worry, if it can't it'll drop a few of them. from the time it blooms to the time the fruits mature, there's usually 2-3 phases of natural fruit drop so not to overburden the tree.

The problem is that there are actually some fruit trees that can fruit themselves to death. I've read tons of documents over the years, and nursery owners over the years that vehemently advocate the doctrine of not letting trees fruit until they reach at least a moderate size. There is variation on this based on fruit size and the other obvious factors. Gary