The main problem here which everyone seems to be forgetting is that he was clearly in breach of contract. He got fired because he broke his agreement with his employer. This happens to everyone, not just people with extremist views. This is not happening to Folau because he is a fundamentalist Christian, it is happening to him because of employee misconduct.
Rugby Australia had warned him about making those kind of posts on social media and in the public in the past. This didn't just come out of the blue, they followed disciplinary procedures properly. I wouldn't be surprised if they said something like, we don't really care what your views are, just don't make controversial statements on social media while you are a representative of Rugby Australia. Folau forced their hand, he put them in a position where they had to terminate him. He doesn't have a leg to stand on legally, there is no way he will win a case against RA.
What Folau is now essentially trying to do is get all the equality legislation in Australia altered so that fundamentalist Christians are the only protected group while everyone else can go to hell. Not only are his ambitions selfish and dangerous, but they are also extremely unchristian. He has gone to the fundamentalist Christians for money who have previously raised legal funds to try defend paedophiles and rapists, so he is not in good company.