Quote from @Elizabeth Rose: @Josh Bowser this tip of doing a quick search on county GIS or software to see if homes in a neighborhood are owned in personal names or LLCs is gold, thank you!

If you fail to follow the rules, you may open your personal assets to a lawsuit.

This would require tenancy in common which lenders typically won’t allowTransferring ownership from personal names to LLC is straight forward with a deed transfer and re-assigning the tenant leases.

I'd look at crime rates and I'd also look at multifamily supply projections to see how many units are expected to come online in the next few years. 

"A smart person learns from his mistakes, but a truly wise person learns from the mistakes of others" - Ken Schramm

Keep personal and business finances separate to create less headache.File all receipts in a dedicated Google Drive folder.

Owners are able to list their personal contact information, but I believe there is a stipulation that the contact must be local to the property4.

I know a buyer that would offer 10% down for earnest money, but he made it contingent on his personal inspection of the property within X days.

I personally sold close to 30 I owned in an ascending market (sold prematurely) and know plenty of others who have had the same experiences in markets across the US. 

As far as my personal investments, I have mainly focused on multifamily - but I do have commercial retail and office investments.