I'm technically the third owner. 

You could just refinance it with get a regular mortgage, you wouldn't need a down payment because you technically paid "cash" for it (the bank won't really know you got a hard money lender to fund your deal).

And that's new information to the seller, you can improve your negotiation position because they are then required to disclose to future buyers is my understanding.On to the technical and again I'm brainstorming out loud here....I have ZERO experience with mud jacking as a permanent solution to slab heaving issues - however I would wonder about the feasibility of this as a 'roll the dice' kind of solution (good money vs value trade off) ...if you buy.One possible solution may be to jack the house and repour which I don't know much about how the bottom plates/wood structural would be tied into the slab - but jacking the house and re pouring sections or all of slab would be an incredibly costly endeavor. 

@George Blower, What happens if you own real estate in a Roth SOLO 401k (avoiding UBIT and financed with a non-recourse mortgage) then rollover that asset to (In-Kind service distribution I believe is the technical way of explaining it) a Roth IRA before the mortgage is paid off and is owned free and clear?

You'll record the interest as an expense and the principal as a liability (see a CPA or bookkeeper for more details).If you are concerned about making interest payments during the flip, you can modify the terms of the loan with your father-in-law to accommodate.

At the last minute he decided to increase value by adding a chandelier, it almost detailed the project, hilarity ensued, and in the end they got it installed.

If you're a rental property owner in Sacramento (preferably on the Grid, but immediate outer-lying areas are great, too) then please DM me with details so we can set up a call.We both have 6+ years of perfect rental history, references, 740+ credit scores and no pets.

I'm also out of state (technically out of country for now), also investing in Dayton OH and looking for similar properties.

It is interesting to see these details for Philadelphia.  

Be as detailed as possible.