Then I offer them a reduction in rent or something and they see it as a bonus.

You could offer to take the property as is, with a price reduction for the outstanding repairs.

If the garage is not built to support the weight of additional floors or is not adequately reinforced, it may not be suitable for conversion.3.

However the way values are rising, those risks get weighted differently.

You can try adding incentives to the contract, like a bonus for finishing on time, or you can add consequences, like a price reduction if they exceed the budget or completion date.

A good property manager is worth their weight in gold!

You buy a chalk bucket, special shoes, tank tops with motivational quotes, kettlebells, a $200 sandbag kit, pullup bands, a weighted vest, a tabata timer, a tractor tire, rope, etc.

Spending a few hundred with a plumber to inspect the lines before purchase could have saved a massive headache or garnered at least a big reduction in price.   

I think having a lawyer specifically look at your original loan documentation and the documents related to the principal reduction will be the best way to proceed.Whether the recourse rights transferred with the loan sale or not, they will still exist.

Bring some options considering the weight and uses, and see what deductions you can use it for.