One of my friend happens to be a RE agent, landlord and a property manager himself and he seems to feel that as long as she pays rent on time and does not create nuisance, not to worry much and just keep do a quarterly property inspection.

But, at second brush, it seems to me like the only properties for which an owner would ask for excess proceeds were the properties I was going to lose to shrew investors anyway.

I will be buying a property purely as an investor so I am unsure of how many of these incentives will apply without owner occupancy.

Additionally, I'd ensure the exterior of the property is always clean and orderly to reduce your chances of having issues with the neighbors.

When refinancing, do you normally have a tenant in place before the appraisal, or refinance while the property is still vacant?

Vacancy + Maintenance/Repair figures you are using will only work for Class A properties. 

Should I consider: Purchasing rental properties?

Because the property tax as a non-owner occupied property is about 3-4 times the amount of a owner occupied property.  

Cash for Keys is a method used by landlords and property managers to encourage a tenant to vacate voluntarily in exchange for a financial incentive.

Toss in a BRRRR strategy with a few other strategies and the potential to live mortgage free and cash flow when you move out of property is real.