Combined loan to value, this is the ratio between how much you owe & how much the property is worth; in general you are looking for a 20 - 25% spread.2.

We would be doing these deals together and our combined gross income is $190k/year.I have ~$80k of capital and am looking for the best way to optimize my investment.

A lot of people starting out do "gap funding" which is up to 100% combined LTV (1st mortgage plus your money in 2nd position) which can go downhill very fast if you don't know what you're doing or your borrowers don't know what they're doing.

Combining your gut feeling (trust/like them) with some data on past and current COVID performance is a good mix...

I'm hopeful with our combined savings and possibly her dad or other private lenders, and my construction skills and time, we can start to lay the right foundation for our future.

I guess those two could also be combined, and I'm considering that too. 

Less cashflow combined with debt payments or other forced payouts equal need to sell.

It seems you have a better chance of finding 4 plexes that are all one bedroom units or a combination of two 2 bedroom units and two 1 bed room units.

You can petition your county to combine side by side lots like that as well. 

That's a powerful combination.