I guess I can't wrap my head around the fact that anyone can make an argument as to how the doors and windows being left open was not the root cause of this issue.

I can tell from your questions that you are in a bit over your head and before you make an incorrect decision you should STRONGLY consider a consultation with someone.

99% of the people would run from it just hearing that.

Either you don't know why because you have your head in the sand and haven't paid attention to their communications or they are trying to hide things from you. 

I will move forward with my journey and just follow the positive people in this group that is amazing.I get the Ra RA Ra stuff.. just sometimes reality comes into play.. and its sad to see people run down these rabbit holes.. when those with decades of experience in the industry know better.. just trying to give both sides..   

I would advise running your rents conservatively and vet property managers properly before signing anything.

Generally there are multiple units for each "zone" if you will when I've seen them installed.Regarding your problem at hand, I personally would simply adjust your plan to move and make your initial plan to get the current issues resolved, while costly now, in the long run holding onto the unit will likely pay off. 

With seller's permission: Unscrew the shower head and put it on shower floor.

- Why would you expect a well-run, profitable PMC to work for free handling maintenance? 

It will be a run down apartment building before long.