So I bought a 4 unit in what i would consider a B class neighborhood. The units have badly installed cheap damaged linoleum floors. I'm looking to upgrade to a flooring option that will look nice, hold up over time, be easy to repair, and not break the bank. I plan on owning this building for at least 50 years.

I'm leaning towards luxury vinyl planks, since they seem to be the preferred choice of investors. However i have a friend who claims water gets underneath them easily and damages them, is this true? Also with the locking kind, what if i need to replace a piece in the middle because it was scratched up by furniture? Can i cut it out and put in a new piece, or do i have to unlock all of the pieces in the same row, until i reach the damaged one? 

Also I don't know anything about underlayment. I was thinking about installing a rubber underlayment in the upstairs units to reduce footstep noise.  (like this: https://www.rubberflooringinc.com/underlayment/2mm...). Is there any reason this kind of underlayment won't work with certain flooring choices, or are there better kinds of underlayment to choose from for noise reduction?