I like the size and the shape of those grow bags, the only two concerns that I wish to mention are adequate shade, and being prepared with enough potting soil.
I have experienced what Kris has. I can go through potting soil very quickly, so I would rather have too much available than too little. Grouping the planted bags near each other will help to provide some shade for the trees, but I would also suggest locating the whole shebang where the trees only get a couple of hours of sunlight each day. This will help decrease the need for water and will lessen their stress a lot. The goal isn’t to grow the trees tons while in bags, it is just to get them successfully through to cooler weather in the fall and then get them into the ground.