Unless it was changed, it gets conveyed through a dialogue by Wen early on. It was said there are 3 preliminary round fights. As in: you can lose one, win two and you´d likely still go through to the elimination phase of the tournament. That should mean probably 5 fights total, at least. Price money also confirmed, the exact amount, I don´t remember if was mentioned. Don´t think it was huge.
As for Mike: speculation, likely driven by potential Gillian-arc (personally still don´t think it´s him) but we have no idea really, other than he´s the only named npc confirmed to be in it so far and roughly same weight class as buff Ian? Maybe there´s even going to be 2 routes, one where you fight him and one where you don´t? Edit: Forgot to mention that there´s obviously also a possible conflict with him if Lena is on his path, while with Ian. Maybe that´s where the 2 possible different outcomes kick in.