Maybe the five of you all agree to cut a check for your 20% share.  

Not everybody is cut out for college.While you are young and energetic I would suggest both investing and school at the same time.

Give them a deadline to complete the project or cut your losses and find someone else that can complete the project ASAP.Lots of hard choices, but that comes with being an actual investor and not all the rainbows & unicorns that many on this site promote.

Be patient, save more, buy a smaller place, move somewhere more affordable, get other streams of income, house hack, cut your expenses. 

If at all possible, I'd suggest beginning with a house hack because it should cut down your own monthly expenses while you build equity and there are great low down payment programs available for owner-occupied financing.

From my perspective I earn my cut whether that is 50% or whatever is decided by doing those things.

What I have seen most Loan Officers do is split marketing costs, but you can't pay more since that could also be considered a kickback.I have also seen companies have realtor's get licensed as an MLO while they handle most of the transaction for them and pay them a cut since they will be the MLO and Realtor on the loan. 

I hope someone else can find inspiration by my story or if you are in similar situation maybe you can take part of what i did and run with it like a pair of scissors in your hand cutting through the mess thats blocking you. 

Seems cut and dry that with limited exceptions JADU can require owner occupancy. 

AS @Kevin Sobilo pointed out this is very STATE specific.some states is quite clear cut others it utterly complex.