The question: Can a Fascist France and Russia form if Germany wins WW1. I would say plausible, although you'd have to work on it. Things could go in a different direction too.
The questions: Would they gang up on Germany? Perhaps, it's certainly not implausible. Here it doesn't have much to do with whether they are Fascist or not. It could happen if Germany showed weakness and France and Russia were growing strong again regardless of their ideology.
The question: Would they win? Perhaps. It's not impossible, depend on in which shape Germany is, who are allied with Germany, who are allied with France and Russia, will the war be a long conflict or will one side collapse early? So the winner of such a conflict depend on several factors.