Replace the system up to code. 

Which is code for "MORE dependency, dependency on D.C. for ALL!!!!!". 

please reply with actual law codes if it’s criminal.

Just offer with inspection period and make sure to have written in -  "contingent upon satisfactory review of all leases and T12, not to alter or change leases during pendency of the contract" (At least that's about how I would write it but the realtor there should know how to specify it).

This all hinges on what you call a "rental property" is actually NOT a rental property in the tax code! 

I don't think they differentiate the rental type for the writeoffs.I've researched this a fair amount, from what I understand there's an exception section 469 of the tax code that says if you actively manage the str and have an average stay length of 7 days or less then it's treated as an active business and the income is therefore not passive and expenses are able to be written off against W2 income.

Any programmable thermostat that has the ability to lock the screen with a pass code should work.

After doing some initial research, I decided to check out some zip codes in Philly as that's an hour's drive from where I live - 19132, 19133, 19134.

I guess about the only thing that would worry me the most would be that if you add to the existing building, and if the city code has changed since after the initial build, then they are gonna want you to make all the necessary changes to the existing portion of the pemb.

My properties have usually been in the 39206 and 39212 zip codes which are a mixed bag.