There is no promise that the beta testers are gonna find all problems, so final beta A is the beta after they tested it, when a lot more people play it. Some other small errors/problems might pop-up so he hopes to fix those for the final version: final beta B
I think that's what he means, otherwise he might just give us the beta the testers played but without all the fixes, only the necessary ones or something like that
Yes, all other versions are being cancelled due to lack of time and other private affairs. However Aethestode has given permission to c067912881to use his yellow sprite if I remember correctly because c067912881 is in the early stages of a likewise project with Yellow.