there are only 2 forks, SegWit and SegWit2x. the first one got everyone's support but the second doesn't have as much.
the bitcoin cash is just a split off to make a new coin like many other altcoins that have done this before. this is technically the same thing.
the nChain is not really a fork, it is something that was proposed for scaling, I don't know how serious it even is.

and any fork can happen at any time. nothing is stopping anyone from forking from bitcoin. you can do it right now too. you just need to have a little mining power and the knowledge of how to do it. these forks will become something only if they get the enough support