I was trying to figure out how to raise capital so that I could build to rent a 50-75 apartment unit in the next 5 years.

The loan is with you, not with your tenant, so none of that means anything to them - in fact because you live in one unit and it's under 4, if you were self-managing you don't even have to abide by fair housing laws (at least on the federal level). 

The good thing about this is you can do a parent listing offering the whole place, as well as 2 other listings for each unit. 

Or are you going to go the safer route for minimal time expenditure like buying a multiplex and renting out 2 out of 3 units?

Expect to spend another ~$8K for that.If you are planning to close all-cash and bring enough cash with you for operating expenses and rehab, you are looking at a minimum capital raise of about $3M and that is for a cheap 32 unit.

Most ADU's are one bedroom units and rent accordingly.

Just found a builder a nice subdivided land in SC they will subdivide into smaller lots for mobile homes.

Ask how many units they manage and how much experience they have.

If you don't think any sort of fee is reasonable then continuing managing your unit may be in your best interest.Are you also keeping up to date with legislative changes in your area.

Hey @Spencer Cuello, so you will find most of us aren't fans of arbitrage.I see you listed NYC so you know that you can't do a STR in the city unless you live there.IE: You need to be onsite, living in the same unit you are going to rent.As per usual...