I can keep a running spreadsheet of everyone I speak to, and follow up with them both via mailing and phone call so that I ensure a number of touches.  

While anyone with the proper securities licensing can sell them, your typical financial advisor doesn't know real estate. 

Either put the partnership together properly or just buy it in your own LLC and have your partners be silent partners.

You'll also want to ensure you're taking full advantage of any potential credits to lower your premium.

Not running fans in the bathroom, running humidifiers, not properly cleaning and not venting dryers properly (as you learned).

To connect our house to the apartment above our garage or "Additional Dwelling Unit (ADU) we had to have pipes excavated underground to ensure that the garage apartment could connect to sewer/water from our house.

I want to ensure they know where to and how to send their next rent to me and not the old owners.

Properly done, there should not be duplication of coverage with the exception of Liability. 

Properly filled out forms from an attorney often go a long way in these situations.

If the Master policy is insured correctly then this should satisfy your lender, however, if the association has chosen to cut corners and is not fullying ensuring the property/building then your lender might require you to purchase flood insurance to balance the requirements of the loan.