@Andy Park given that the tenants are month-to-month I would terminate the existing lease and create a new one.

A real estate is a place where lots of opportunities exist.  

Analyzing other markets should be the norm...your current market won't be offended.90% of the REI time spent each day on REI should be spent analyzing new markets, and reanalyzing existing markets. 

DIY forum online folks suggested jacking/raising up the existing shed and fixing the perimeter with brick or concrete, etc. to mount the shed onto.

When purchasing a leased property, must you always honor the existing lease?

If you're going to rent the properties out and keep the existing mobile homes there, you'll just have to figure out the market rents and expenses for each unit.

I"m seeking to rezone the lots as they are pre-existing, prior to the first zoning codes, which later came in and only granted duplex zoning, so these are legal, non-conforming but can't be converted to separate up/down "condo" sales as lenders won't loan if a structure can't be rebuilt after a catastrophic loss unless its zoned correctly as their collateral is compromised and that is the case in the county where these are located. 

No, the 203k cannot be used to build new unless the new is connected to the existing. 

That contract gives me rights and interests in the property that wouldn't otherwise exist; which is why suddenly I care about them a lot more than I did before.You're not marketing a house.

As for getting rid of existing stains, CLR works pretty well.Good luck!