Due to Covid-19 my two roommates lost their jobs and I want to move into a 1BR apartment as they will no longer be able to afford rent.

Think of house hacking more like having some room mates.

To give you some perspective on rents in the area, my girlfriend lived right in front of Norris Square on Hancock St in a 2 BR/2 bath apartment with a roommate until August of last year and they paid $1800/month, so for a large 4BR home nearby you could probably be charging at least $2k+.I bought a 1600 sq ft 3 BR/2 bath fixer upper in May of last year and did (edit: still doing) a full renovation.

There aren't any listings for roommates or room rentals for the area.

Question #2 - Living Arrangement: I know that while I'm living in my current home, charging my roommate low rent and not renting my 3rd bedroom I'm not maximizing my ROI.

It's just a modern term for having roommates (does not need to be in a fixer property). 

Turns out, Mike also decided to move out without notice, due to one of the roommates being a horrible person.

I have around $100k equity in the place.I needed some advice on the following things and tradeoffs of each, namely because I'd like to live by myself now but I feel as if I'm stuck with this home somehow due to high cost without roommate, banking only on appreciation in Bay Area to carry me through.

You put up the down payment and take care of the mortgage (with help from roommates), they would just share ultimate responsibility in the event of default (so not a commitment to be entered into lightly..).

Move into the house and get a roommate, preferably two. and do this until I have 5 rental properties.