On the surface I'm thinking rental, either long term or short.

I've attended a few where there nothing but beginner investors and the main person is speaking on surface level stuff.

On the surface your motivations sound noble, but I don't see how your approach would make an inroad into the issue you hope to work on. 

Everyone's interpretation of clean is different but sanding and refinishing will remove that dirt/stains, level the surface, and seal it making it 2x easier to clean.

If you have baddies in your water, PEX will give them a surface to grow on. 

So if your basement wall is leaking, the root cause is almost always unmanaged surface water.Gutters: take a look at a downspout during a thunderstorm - it looks like a firehose!

Most importantly: manage your surface water, gutters and downspouts - the root cause of most basement issues.

They also should not be allowed to drain onto a sidewalk or other walking surface creating a slipping hazard; or be located in a hazardous location that can cause injury to unsuspecting pedestrians, such as protruding low over a walkway.

Anyways, in reading through the pre-license coursework, a good 75% of the material I already had a pretty solid surface level understanding  of from my previous year or so consuming BP forums and podcasts. 

Soot left on metal surfaces can cause pitting and corrosion, example faucet sets, door knobs.