You can spend time and money fighting for this, which may well land you with a small percentage of a company that may or may not go somewhere - and a small percentage that will doubtless be diluted over time - or you can move on with your life and forego that stress and expense.

Only you know how far the project can go with what, to be honest, sounds a fairly chaotic group of people steering it. If you really think it's worth fighting about then go for it, with the awareness that you may expend time, money and emotional effort but still end up with nothing much. Otherwise, move on and make something else, and something better.