Nothing in writing. Everyone's saying I should just drop it, but I'm thinking I should try to salvage the situation by dropping the ideas guy and coming to a formal agreement with the angel investor.
You’ve essentially been a discount contractor this far with a handshake agreement about ownership.
Right now, there is no business, just a product.
You’ve probably done whatever was initially agreed in terms of a demo and it’s time to talk next steps. You need to go into that negotiation with a frank understanding that you may need to walk away.
Aim to get (in writing) an agreement about what further funding for the business would be, and what the actual expectations on you are (in terms of time and deliverables). If they can’t do that, walk. I don’t know you or the ideas guy or your investor, but I feel that if you have an MVP, you’ve done a whole lot already. Definitely discuss, but you have to actually come to an agreement (with both parties, or just the investor) about real numbers, and a legal entity that is going to be the business going forward.
Of course, don’t give anything away that would identify you too uniquely.
The fact that the other two shareholders have nothing to offer but setting up the money and business side have allowed it to be setup so badly at this point says it all.
But hey, you can hedge your bet. Just say, "ok guys, it's done, here's the demo. I hope we can succeed with this. Excited to hear updates"
Then simply move on to getting a job or other paying work. If they come back with any success and you're available then you can say you need a monthly wage to continue. Do not do anything at all with it unless you get that. If you get any "come on, I just need X to close the investor" just say "sorry, I'm not an angel like you.. I need to do this other work to pay my rent.
It doesn't matter if that is literally true or not, you do NOT have to be completely honest in this context. They sure haven't been honest with you.
Even between friends, paperwork makes sure everyone knows who is committing to what. Prevents bad feelings.