You might check out the book/concept called Slicing Pie by Mike Moyer. It addresses situations like this. The quick summary is to allow equity ownership to cha

You might check out the book/concept called Slicing Pie by Mike Moyer. It addresses situations like this. The quick summary is to allow equity ownership to change based on work done for the company that is not paid out in salary. Start with an agreed upon value of the company(example $100K). Everyone has an hourly pay rate. So if you all do 10 hours and don't get paid your ownership percentage stays the same. But if 1 person does 100 hours of work and doesn't take salary and the other people do 20 hours and no one gets paid actual money then the overal value of the company goes up by 140 hours time pay rate. And your ownership percentage changes based on how many hours you contribute.