You have a fair amount of capital, you should save that up in case you need it for personal expenses throughout your business journey.

□Do you have a separate bank account (check or savings) for each LLC?

In most cases my dad trashed it but if it was "good stuff" he'd save it and once or twice a year have a garage sale. 

This year I didn't spend anything, saving up for the flips. 

#2 Should I buy what I can now as long as its cash flow positive or should I wait and save up for multifamily deal where cash flow will be more?

Business Start Up Expenses are intended for things like market research, consulting with lawyers and accountants, researching business locations, etc before actually going into business.Remodeling expenses are remodeling expenses.Also, no ad in the world is going to save you from the "Asset in Service" rules if the property is not actually habitable. 

Still have around $20k in low to no-interest debt, and have about $7500 in savings. 

Concentrate on savings, living frugally will be your best approach to increasing savings.

Even if you only do this for a year, the money you will save yourself up front will be substantial. 

That's a $300 deficit which doesn't sound bad since you will be living in one of the units and saving approximately $500 in rent.