Use the product "Red Guard" before tiling and be sure the returns and sills are prepped this way.

I looked at them and honestly I did not see where there was enough meat on the bone.

Orange is communications (red=elec, blue=water, yellow=gas, green=sewer, forgot what white is).  

How are such deals usually structured to ensure there is enough meat on the bone for the developer? 

One housemate wants to blast the AC until the place feels like a meat locker, but another prefers no AC.

There are just too many red flags here (including your inexperience) for this to be the right first MHP deal for you.Attend F&D's bootcamp (www.mobilehomeuniversity.com), get educated.  

I do not want to sell, so I am estimating a moderate $400,000 value which should still put me at plenty of equity to get a $50,000 loan.

Red flags to avoid?

Lots of issues to consider like title insurance, due on sale, comingling of funds, IRS red flags etc. 

Quote from @George Red: @Timothy Burns fingers crossed for you... sounds horrible.