I greatly value constructive criticism, so lay it on me (gently)!

A bigger issue to consider is where the moisture is coming from and how to reduce it.

You may even be able to pry from the sides and gently pry them away in such a manner to save them and sell them to someone else in a yard sale or Craigslist.

If you decide not to tile, be sure to at least use greenboard/moisture resistant board, as most older homes have regular drywall in the bathrooms.

And the next time the tenants were gone I would hear water running in their unit and have go in to investigate in every corner of the place for moisture.

I think I may have a moisture problem at the back door so I am planning on replacing the door.  

Needless to say we were fairly stoked that he agreed to speak with our little group.Through the power of the internets, Skype and an overhead projector, we were able to beam his smiling countenance onto the screen for all to see, like Big(gerPockets) Brother watching over us from some Sci Fi flick... only a kind, gentle Big Brother with a beard, a mustache and cool microphone.He then generously answered questions from our members for the next 30 mins.It was incredible that even though Brandon was halfway around the world, it felt like he was in the room with us. 

it is a little uneven, partially cracked and I see moisture is getting there on the edges close to the walls. it is not swimming in water but definitely wet.

I gently told her maybe my offer would be her miracle. 

One other point I have is to make sure the bathroom has a good proper sized exhaust fan, steam moisture does more damage then anything, I also try to have the overhead light wired with the fan so when light is on, so is fan, saves those tenants who cant get the point of the fan or that it actually needs to be turned on to work.My home bath I installed a push button timer switch that has different settings ( 10,20,30 etc) saves the kids from leaving it run all the time.