There are very strict environmental laws and the removal/ water testing process and or treatment can become quite pricey.  

This could end up being the unofficial "phase 1" of this project as I'm sure there are smaller multi families out there that would need this treatment. 

While I understand that you are looking for an inspection/treatment company, with the details provided, you may be putting the cart before the horse.  

T & I is $317, HOA is $339, so monthly cash flow is (-64) plus a couple hundred bucks a year if the toilet clogs or something.I feel like I'm letting the favorable tax treatment at sale and the low mortgage rate guide my decision to keep the property, since negative cash flow is never ideal for a rental - but I also love how low maintenance it is, and I can also see myself moving back into the unit one day if I ever get divorced or if my husband pre-deceases me.    

Generally, in order to buy a replacement property, make improvements to it and have both the purchase cost and the improvement costs qualify for 1031 Exchange treatment, the legal title to the property must be acquired and held ("parked") by an Exchange Accommodation Titleholder (usually a sister company of the Qualified Intermediary) during the 180 day exchange period. 

The treatment plant owner wrote a $300K check to fix his problem. 

Needs a termite treatment, but we're trying to get sellers to cover it (they are selling as-is).

In my experience as a lawyer working these deals, a “self employed” person who takes a W2 seems to get better treatment than one who has no W2.

The other two units would qualify for 1031 Exchange treatment. 

Look on Craigslist for properties that are nearby and have the same bedroom and bathroom count, garage/storage options, and matches utility treatment and pet policy that you intend to use.