Grafting and espalier
I have a little experience with both grafting and espaliering. My first note is that some trees take to those "treatments" and some don't. Best to ask your plant nursery expert to help you select species and varieties that will do well with those treatments.
Grafting isn't hard, with a little practice (and the right trees), you should be able to graft successfully. When done correctly, a grafted branch should be nearly as strong as the original plant would have been. I think that grafting is a good skill to have, and suggest that you give it a try so that you build that skill. There are good books on the topic, and you can probably find good instructions online as well.
Picking the right trees is even more important with espalier. You want to select species/varieties that naturally have a lateral-growing habit (vs an upright/columnar habit). You will need a "structure" to tie the lateral branches to to train them to grow horizontally, and the espaliers-in-training will need a fair amount of attention to get them to grow correctly and keep them that way. Again there are good instructions in various books and most likely online as well.
I've always found deciduous trees to be pretty forgiving – my advice is to go ahead and try your hand at grafting and espalier. Don't be shy. You will learn a lot as you go; and the absolute worst thing that can happen is that you kill the tree and have to replant and start over – which isn't the end of the world. Equally possible is that you are completely successful, find that you can expand your fruit production for a much reduced cost, and end up having a marketable skill. Good luck and have fun!