Second rental property as a duplex.Converted SFR, first floor 4br and 1 bath ($665/month).

Gutted the floors myself and installed new subfloor and new flooring on entire first floor.

I installed some updates like new flooring and Kitchen appliances.

Can you arrange for counters, floors, painting other “basics” without him tacking on his 20%?

floors?  

Painting and flooring are super easy.

I think you are looking at the wrong places, insulating the floor wouldn't change much. 

I will also be doing all the cosmetic things you can think of: paint, flooring, bathroom reno, kitchen reno, so I am open to carpenter or design suggestions.  

Quote from @Ricardo Polanco: Good evening everyone, I am evaluating the possibility of buying a multifamily property in Scranton, at this moment it has 2 apartments that only need cosmetic repairs and it has a big 2nd floor unit that needs a full repair.

You mean the water was so heavy that it cracked the floor joists and the entire floor and basement ceiling fell in?