.: Quote from @Jaron Walling: Follow your lease.

It's laborious, messy - but it was far less damaging/challenging than the photos found on the internet...even with plastered walls.  

Don't look for lowest rate, look for lowest cost on fees as you will either refinance out of that loan or sell- the prepay will hit you on the back of the head like a cinderblock wall.

Is there a clause stating he can't remove the copper pipes from the wall? 

Doing so usually cracks the walls and can make door jambs out of alignment.

Quote from @Jaron Walling: This question seem pretty naïve for someone that's flipped about 30 houses. 

Current Tenants- would some want to expand into units next to them, knocking down wall, etc.7. 

It all depends on the walls you are hitting.

-Structural (foundation, wall, ceiling and floor)-Roof and Exterior(Roof Condition,Gutters and Downspouts, Siding, Windows and Doors)-Plumbing (Water Pressure,Leaks, Drainage, Pipes)-Electrical (Wiring,Outlets and Switches,Breaker Panel, Lighting Fixtures)-HVAC(Air Ducts, heating and cooling)-Water and Moisture Issues(Attic, Mold and Mildew)-Kitchen and Appliances-Bathrooms-Pest and Insect Problems-Safety Features

In order to continue, you must select “Okay.”You will then be prompted to select the privacy settings for who will see your Tweets and Retweets posted to your Facebook wall.