Of course the co-signer should be significantly stronger in ALL areas as compared to the applicant...usually this is a parent or relative, and they should be well established, with ownership of real estate for years; long and stable employment; no, or very distant, criminal and traffic court records; well funded SAVINGS/IRA's or stock market accounts.

@Sandee SampsonA construction attorney would be who to contact but you are going to spend a lot more than $7000 in getting this resolved against a builder.Also let’s say you win, the courts could also say you didn’t pay for a retaining wall which is needed so it’s a betterment to the property so you would still need to pay for the wall and they would be responsible for some soil etc.

I've seen success in Washington Court House, Ohio.

They use an eviction service for serving the tenant and coordinating with the courts. 

Focus on key areas first (like floors, walls, kitchen, or bathroom), which may help you handle the costs more gradually, even if it means moving in furniture or updating fixtures down the line.Also, since the tenant left it in rough shape, be sure to document all the damage (photos, receipts) in case you decide to pursue reimbursement through their security deposit or in court.

However, if you do anything illegal and you have to defend yourself against Mexican nationals, entities or the government in a court of law in Mexico, good luck to you.And this is where the problems lie.

Always do your due diligence folks, search for their name on here, check for criminal and civil court cases in the county they live/do business in, etc. 

Of course, the tenant didn't want to pay for them, but lost in court. 3) Use this same language for ALL appliances: stove, fridge, microwave, dishwasher, washer, dryer, window ac, etc.

Without a written record of this arrangement, is there a way to claim any compensation for those renovation costs, or would that be difficult to prove in court?

This is gonna be a learning experience due to dealing with environmental court.