Looks like a really great start to a clump. Agree with
@Bonsai Nut presently a trio of trees.
One could, and it might be really cool!
Yet the overall effect likely might not be in harmony unless one gets exactly the right match of foliage, color shades, bark and growth characteristics. That would be really hard.
Rarely seen it pulled off. One Japanese master was fond of creating multi species forests, but even then he didn’t mix these much, mostly separate stands of trees.
If one is new, best to stick with the same species. Would recommend
https://kaedebonsai-en.com/ as a good place to source nice Japanese Maple seedlings.
Cheers
DSD sends