Let's analyze each issue you've mentioned:1) Tenancy Length: besides issues a landlord can't control, like death, sickness, job loss, etc., the actual management of the property & tenant play a large roll in how long tenants stay in their home.

But you do have to put some language in your lease  agreement or lease addendum that deals specifically with issues that will come up for the fireplace.  

There's a good chance the issue(s) you face has already been discussed and answered.Ask questions in the appropriate forum.

That has stopped but we do feel it to be a security issue. 

In addition to those above-referenced issues related to conversions, the additional unit(s) would require a parking space and enough lot area/gross floor area to meet the requirements in 9-703. 

The only issue is with a bit lower rent there's a higher number of applicants that won't qualify but I don't mind the volume to get it filled. 

You may have to sell the whole property to access the funds in the IRA or 401k when you retire and for required minimum distributions. 

Depending on how you are acquiring these properties you may be able to just do one per year but that only matters if speed is an issues.

Quote from @Ed Hoffman: Are there any issues/problems If I want to purchase a rental property in Pennsylvania with my New York York LLC? 

If there are any issues with the borrowers, I don't have to deal with it.