This puts pressure to defer maintenance and leads to special assessments.Whatever you decide, you need to find a realtor that specializes in investment properties, is well connected, and knows the areas you're interested in inside and out. 

Are there any property mangers out there, or those who would recommend one, who have significant experience in managing properties with these tenants (or, who specialize in this space)?

LOLNow, some have said a net listing can be done in CA, with additional disclosures, but they still have to contend with restrictions as a Special Agent in self dealing......so it appears....LOLAnd here, all along, most thought James Bond was the only Special Agent!  

You can use a custodial account or if you wish to have more control special purpose LLC can be utilized to gain checkbook control and minimize custodian fees and eliminate their involvement in the investment. 

I do not think special education for RE agents on this is a requirement, but it is simply a niche for real estate agents didn't explore, they ask themselves where the money is?

The rationale is that you want people to know you specialize in that particular niche and want the website visitor to know that.  

do you have to be a realtor, broker, or any special certs?

They are common for years in other parts of world (I see many in Europe where the heating is often primary radiators (no ducting) with Splits providing supplemental heat and AC). 

They specialize in helping folks like you.

There are specific CTL lenders out there who specialize in it.Cap rates on single free standing have compressed so much that buyers are using local banks and using short term debt to eek out cash flow with personal guarantees.Regular CMBS lenders that are non-bank see a lot of risk.Buying a single NNN building for a 5 cap versus an 8 cap 3 to 4 years ago doesn't make sense because I can get a strip center today at an 8 cap and diversify my risk among many businesses instead of one.The rent per sq ft and cost per sq ft is lower and you tend to get more valuable dirt with 2% rental increases for strip centers.