In the next couple of years I will look at whether the long-term appreciation approach is practical.

I'm open to this but would like to charge a monthly pet fee or a one time fee (per a year long lease). 

You might also be a good candidate for a small boutique hotel, an operator looking to retire will often entertain seller financing on fair terms and you could likely qualify for a SBA loan to help with your vision. 

I heard that short term loophole is a one time benefit that you get the year you start service.

I have some good folks now but it took a very long to put a good team together. 

Is there a standard letter that I need to send tenants a month before the end of their lease to remind them to move out by the end of the term?

Which is the smarter option to take financially in long term, buying a new construction or resale house as a primary residence?

It might be easier to treat it as a full scenario with Purchase price, Down payment, Term, Prorgam, occupany, number of units/rents per door, Taxes/Insurance (Any flood, HOA) etc. 

Depends on your long term outlook.

. - These are the two channels where these companies will seek out listings for their housing requests.Longer term you should be networking with businesses in the area that are known for having housing needs for their employees.