At this level of scale, it is almost the same as running an extra unit.

Maybe this won’t be a problem if you’ve got just 1 unit but I’ve now got 4 tenants paying $200-$400 multiple times per month and it gets confusing.

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). 

Im a medium sized operator - 46 units- and my typical deal has an ARV from 200 to 230 when its finished.

The management company just didn't do a good job of providing details on bills and never checked on the units.

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.

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.

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