I forgot to mention that the applicant lied about his criminal record on the application.

(If they lie about anything, what will the future relationship look like?)

Unfortunately, Fanny Mae is telling me that they don't actually own the property even though they do according to the tac assessors office. 

These guys are giving me fraudulent numbers and lying about payouts on their Excel doc.

In the end, the seller was rejected (more for lying on the application than anything else).Know your state's (and if applicable, federal) laws. 

Three options, lie to them, walk away, or suck it up for 12 months.

If they are savvy investors, they will have a new LLC/entity for each rental property they own.I think what you need to do is go to your county assessor's website to find where the tax forms are being mailed.

Paying taxes sucks, but not being able to get another mortgage because you lied in order to save a few grand a year is worse.

That's why I have to also consider finding independent assessors, though I haven't really heard of this so maybe that's not really a thing people can do.

I recommend you conduct an online search of the property at your county tax assessor's website, or visit the office in person.