Recommendation to buyer is to engage contractor to inspect the property to verify the accuracy of this estimate.

Thats the point of broker cooperation, the MLS', etc.For some, a "great" Realtor is one who provides value by helping to vet incoming offers, taking care of inspections, helping with negotiations (depending on whether you use attorneys, sometimes the realtor provides another helpful line of communication), and being an experienced guide to a real estate transactions. 

Wanted to solicit this group's opinions ...A group member reports that for one of his SFR units, the rent had gone two months late and he was unable to contact the tenant.Upon physical inspection, the front door was locked, the back door was not.

Should I be asking to have an inspection or is this something that is not done for a wholesale deal. 

Unless you have a background in historic building restoration I wouldn't recommend that.That being said - definitely get an inspection and try to find an inspector familiar with old buildings. 1920s buildings have different common pitfalls to check than 1950s buildings and 1990s buildings.

I have so many questions to ask the listing agent but however seems he doesn’t want my offer because he is selling “as is- non disclosure” and did not respond to my request for a 14 day inspection contingency.

Is it necessary to plan the annual termite inspection plans or can I drop them?

Go and physically inspect properties in your chosen area. 

Get an inspection, make sure you don't need any major repairs and scrutinize the rent roll.

And because $462 is well below the best practices for contingency savings, you should expect to fund emergency expenditures out of your own pocket if they arise early on.This is where a thorough inspection comes into play.