I have seen this before and it's not long before the whole works comes down.So my question is, has anyone seen a semi permanent (5-10 years) fix by buttressing the corner with steel.

Having an experienced Realtor to advise on this stuff is great, but not a permanent or realistic solution. 

We still need a permanent fix but the guy they sent can't do that.

There are solutions that are relatively permanent and some, like lease option, that require many of the lesser expensive compliance steps, but not, (in many states) licensure which is the most expensive step of all, but may not survive recharacterization by the CFPB down the road.

Either way, get out of the "duplex w/ an ADU" permanent holding pattern purgatory. :)Alternatively, you can seek portfolio financing.

John i believe concrete is porous and oil will not permanently come off. kind of like shampooing a carpet, it may look clean for a short while but that stain is guaranteed to return.

Replacing the shower valve is a problem that will usually lead to a bigger job too.The cheapo permanent solution is to remove the old tub and to come back in with a 3 piece fiberglass tub and surround.

It looks like these are park models built on permanent foundation, where my project was involved with what we used to call "THoWs" tiny houses on wheels, which are now being called 'movable tiny houses' by the tiny house code-inclusion advocates, for strategic purposes. 

You also need to give notice that you intend to enter the property to change the locks.Your tenant is preparing to set up a permanent camp.

Questions to follow in subsequent posts ;-) After having the opportunity to live, work and play in the Florida Keys, I came to the realization it was fun and I wanted to make it permanent.