It is also important to inquire about any potential zoning issues or legal issues that may arise during the renovation of a burned home.

The lender would have had an appraiser issue a opinion of market rate rent for the apartment on your duplex so that's a start on what the rent should be.

I see investors who I have spoken with have issues with appraisals which heavily affect their loans, they have worked with certain companies that don't appraise correctly and even admit to it.

Do your best to mitigate issue before they crop up and annoy residents.Maybe create a free service, for those that are not using your management services, to come and review their STRs for safety, procedures for help etc.

Your duty to disclose is a local issue.

There are two issues I want to point out at the jump:1) 1031 exchanges are designed for long-term investors. 

Sure, it's minorly annoying ... but if I got a call from someone who was able to solve a big problem for me and was nice and polite all the way through, I would have absolutely no issues with that.

This makes a lot of sense to me, you wouldn't want them knocking on your door 24/7 for simple issues.

What else would they have issues with if they were moving in.Will they become nightmare demanding tenants?

The clerks that answer the phones are not privy to Codes and what applies to your problem/issue.