I say RIGHT processes because there are many landlords out there that go into investing blind and wonder why they have an bed bug infested unit that is going through eviction and draining them of all their cash. 

I would get to it quickly before the infestation spread to the residential units.As to MA, believe the following may apply: MA Pest control

I found this from the HUD (if it helps:) https://www.hud.gov/sites/documents/4155-2_4.pdfTypical conditions that would require further inspection or testing byqualified individuals or entities include: infestation – evidence of termites inoperative or inadequate plumbing, heating, or electrical systems structural failure in framing members leaking or worn-out roofscracked masonry or foundation damage, and drainage problems.Sounds to me like everything you listed wrong with the property is what caused the appraiser to give a C5 and the deal cannot proceed as so. 

We have put in an offer on our our first property and have been advised of an infestation of powder post beetles, after we made the offer.

All of these houses have had termite infestation at some point, either dead or still live.

I have heard quotes for $200 a year for a termite bond that will do annual treatments and cover all treatment and repair costs should an infestation develop.

There is one that could use a little better house keep skills, but not bad enough to contribute to a huge roach infestation.  

If you let the tenants handle this I'm pretty sure it'll turn into an infestation. 

Usually these properties are corrected immediately by the owners and it is no longer an issue.Once you start getting into illegal conversions, abandoned properties, mold infestation, dilapidated structures etc those are the good ones.

If the whole area with surrounding properties is also crime infested then it's more an area problem then a property or complex issue.Mobile parks you will deal  many times with tougher tenants and have more turnover.