However, required downpayments were typically 40-50%, and would be difficult without a residency visa.

For example, if the typical rent per unit is $1,500 (3bd 2ba), my landlord at the time would have one unit with three rooms and four people within the unit (one person per room and one room with two people), each paying around $500.

My grandfather was a bus driver in Milwaukee and when I spent the summers there in the mid 60s I would ride with him all day on the bus.

Ensure you collect a proper security deposit (typically one month's rent in Florida) to cover potential damages.Your plan to increase rent next year makes sense given rising costs (taxes, insurance, and maintenance).

The typical term of this loan is 12 months and rates range from 10%-12%.

This new twist of claiming you owe them money is a typical scam tactic to put you on the defensive so you won't contact them about the money they actually owe you. 

If cash flow means you make $8 more than your mortgage payment in month 4, awesome, you have $8 for that month.But.... if you factor in closing costs, make ready costs, leasing costs, repairs... it's typically years out until TRUE cash flow, with a value add or a turnkey (unless you absolutely knock it out of the park with a BRRRR and then somehow cash flow after the refi, which I guess is possible but very unlikely.)

In southern CA, even garage conversion ADU additions are typically costing more than the value added.  

I know DSCR lenders typically don't touch them.

Older homes will typically have systems that are out of date - even if only partially.