There are 3 full time developers and there are developers who are actively working on projects that will work exclusively on the Byteball platform.
Who are the other Devs?
I don't see their names in public forums and don't intend to be the first person to name names... but if you look at Tony's contributions and commits on github and see what has been built in the last year it's self evident he's not working alone.
AFAIK @Punqtured from slack has recently taken on translation efforts. He seems to have accomplished a lot in the little time he has been working on it. I don't know if he's going to tackle the bots (since many are third party submissions) but that's a good point.