@Pierre Luc leblondForeign investors have to be mindful of ECI(Effectively Connected Income), FDAP(Fixed, Determinable, Annual, Periodic) and FIRPTA.There are also instances when foreign investors need to apply for an EIN and file a US tax return.You may also want to understand the tax treaty between the US and the country you are from.You should understand the above implications before investing in the US.

Keep in mind that you're offering to pay for something that you didn't determine the amount. 

First you need to understand if you are even allowed to do what you wanna do. towns get split into "zones" and depending on what zoning you are in, it determines what you can do in your property.

How do you determine the cost or estimate costs of a full rehab?

That will determine the next step.

How exactly can you be sure the rehab and ARV is determined accurately?

Now I have to go back to the drawing board, I am trying to determine if it's worth getting a lawyer in hopes that I can get a judgement against him and ask that he pay my lawyer fees (I'm not sure how that works since I have a civil case.) 

If you don't re-program the master, anybody in-the-know (like me for example) can pull two screws and determine the master code. 

I'd back up one step and determine your WHY. 

That’s just too vague.How can I determine what the market rate should be for this property?