Third, the typical person renting a room is not a home buyer candidate. 

They'll typically leave behind mattresses, couches, broken furniture, rotten food, etc.

Typically people think FHA because it's what's thought of as the least amount down which is commonly the goal when we all get started.

Also, there’s much to delve into on of those scenarios, like what type of cashflow or investment do you want, etc. residential, multi-res, small multi-res, commercial, industrial, etc.There seems to be fewer deals around these days and this typically benefits the more experienced and skilled investors but there are always multiple investors that get “tripped-up” in these markets due to them relying on recent “fortunate” market circumstances only to realize the markets cycle and they weren’t prepared or didn’t underwrite properly to account for unforeseen potential.There are more considerations, but this is a start.

Essentially though you need to go off-market.

It will include a compact bathroom, a tiny kitchen area, and a heater—just the essentials to make it comfortable for someone to stay in.

Bonus, Overtime, and Commission income all typically need a 2 year average either at the same job or in the same line of work.

DSCR loans typically require 25% down, and have higher interest rates and fees.

There are more buyers for SF homes, but Multifamily properties typically cash flow better as you mentioned. 

In investing that's typically done by exchanging one asset for another rather than using cash as an intermediary (which would require you to time the market perfectly).