It was such a mess I pulled it all off before the mortar could dry resolving to at least get it properly started myself.

When you store a dishwasher or washing machine, the rubber gaskets tend to dry out from lack of use, which means your appliances may start leaking when they are installed again.Best practice: tell them to sell their stuff and use yours.

They were framed with slow grown and naturally dried timber, which is much harder than what you can find at Home Depot today.

I guess you could check by straddling the toilet and rocking it with your knees (aka the dry rot test)?

If you come up dry there, you may consider just helping her find a more affordable place.

Sounds like you guys have a dry powder to work with which gives you a ton of options going into this cycle.   

There were maybe a dozen large dry wall holes to patch (larger than nail holes). 

Typically, I'd keep taking out mortgages with 25% down until my fund were about dry, but that strategy is getting old and boring to me (though it has been successful over the years).

The bathroom has modern gray on white vanity with drawers, walk-in shower & gray subway tile with shampoo and soap inserts...all this covered with a brush nickel frame shower door.

If you have no problem doing lawn where there is far more black mold you should have no problem ripping out moldy dry wall.