We currently own the rentals under our own names (instead of LLC), and we've heard from enough podcasters to skip LLCs and get a big umbrella insurance.

If you do skip this one - no big deal - continue with the plan to build up reserves and pay off short term debt. 

Skip-tracing your "co-owner" is the first step.

I notice you skip right over the heart of the matter, which is HOW is one looking for an under-market property.

From what I understand the two best strategies are Skip tracing - Cold call or mailing.

I'm interested primarily in MF investing, I would like to skip residential MF and go right to commercial and start with about 10 - 30 unit bldng.

LOL Truly when 50 Years old has feeling of 25 years old again, skipping donut is the easiest one to do.

While it is not the "norm", I have heard stories of those "poor tenants" causing tens of thousands in damage and skipping town.  

Close to hospitals and amenities.Should I just skip over this house?

Those markets are not impossible to crack into but it would require putting some money into skip tracing (you can get a virtual assistant for like $20/$25 per hour who has access to and knows how to work a propstream platform or an equivalent.