Laid black plastic down first to keep the weeds down and covered this with mulch.Despite there being a water spigot ATTACHED TO THE END OF THE RAISED BED the only water these poor things got from the tenants were rain that dripped off the roof. 

On some of the lower priced showers we have installed plastic laminate shower doors. 50% the price of glass, much lighter & after one shattered it was the safest option. 

Check all vents, A/C vents, heating vents with plastic sheets over and taped it.

You could put out some bright colored planters and some beautiful taller plants in those that will dress it up.I'd maybe do some interior lighting around the windows to give it a pop if that's what your looking for, I work in a old traditional building,, we did LED track lighting that's in the plastic tubing around the main floor windows and really pops when you drive by. 

Tar the cracks and put plastic over followed by another layer of tar.

The tenant has closed off the upstairs with plastic sheeting and moved her bed into the living room because she couldn't keep the upstairs heated.  

We hated to replace some of the flooring that was almost new, but they had used two different faux wood patterns/styles that clashed, and it looked somewhat cheap and plastic.  

I ended up repairing it myself but I was on the way to get a new faucet aerator (since I broke the cheap plastic aerator trying to clean the pipe thread sealant accumulated from the pipe repair) when I was T-boned by a guy with no insurance. 

Once painted, it’s basically wrapped in plastic which traps that moisture inside the wall making mold much more likely as well as causing damage to the brick over time, which could even compromise the structural integrity.

Either way, it's PVC plastic - it's not going to crumble or start leaking or anything.The pic inside the wall shows wood planks for sheathing.. which is what they used until the mid 1900s (they use plywood now because it's cheaper and goes up faster).