This is a futile thread. We can't really provide any useful information. It's impossible to tell exactly what this is. Best source of info would be from the place you got them. There are hundreds of varieties of Japanese Maple, many share extremely similar leaf shape and color.
In any case, all this really doesn't make much difference. All JMs will get similar care and procedures for bonsai are mostly the same for all. What does make a difference is the first one is grafted. It's a low graft that's pretty well done, but there's bark mismatch, which is common. Not a deal killer, but it will bear watching for suitability for bonsai. Sometimes the mismatch gets worse, sometimes it blends.
The second tree is two trees and they could also be grafted. Their nebari looks, well, "challenging" and its something you're going to have to get a handle on next spring. The roots look like they're going to be "stilt" roots once the soil is moved away, that is, individual roots that take a direct deep dive into the soil with no surface spread to speak of. That will mean you've got to make that happen over the next few years--through hard pruning of the roots and flattening techniques, such as fastening the root mass to a board, etc.