It now looks pretty bad even though I put a rubber suction mat over it so it wouldn't chip further.

Then the only problems we had were not getting the pipes cleared out for winter completely (because they "settled" with low spots over the years) and freezing/bursting the the lines causing large suction leaks when we fired it up in the spring.

If a rental or a flip you need to know what other bathrooms look like in the area as to finishes and quality expected.Example it has an older insert tub.You want to rent out.You find out that as long as the old tub and shower is clean tenants will pay 800.With a new tub and shower they will pay 820 a month.Putting in new say costs 1,500 for example.It will take you a 20 a month 75 months (over 6 years) to recover your money.So your answer depends on what you are doing with the property.Not just for the mold but the fixtures,valves,toilet,and supply lines for the sink and toilet etc.If you get a contractor to fix this they will charge a mint.If you get a mask and take it out and just put cement board up you should be fine.You need to make sure exhaust fan works,is proper size and suction rate for that size of the bathroom,and is properly vented to the outside of the property.Make sure roof is properly vented as that could cause sweating and mold problems.If you look into the attic and see mold on the underlayment of the roof boards then you either have a roof leak or a breathing problem.The roof vents for air going in and out (cycling) could be too small ,in wrong location,or too close together.Hard to say without being there.No legal advice.

Not enough air flow to release suction of the water.

In a foreclosure by the first, the second gets wiped out....if the suction bid was for more than the first was owed then the second would get the surplus funds. 

Think about what you are vacuuming and what power and suction you need for the job.Vacuum cleaners that do not have a disposable bag are a poor choice.

I use a shop vac and duck tape a scrapper at the suction mouth area.

They do not have the suction power to to do anything but very light touch up work on carpets.

Many come with their own little collection baggy or canister, but they fill quickly and still don't do nearly as good a job as the powerful suction from a shop vacuum.

The paste turns color in the presence of water so the pump suction will only be inserted to that depth.