It is always going to be painful, though, because our tax code is set up to punish you for excelling.

If you were caught moving before the year is up, there could potentially be life-changing penalties as this is considered mortgage fraud by the FBI with penalties punishable by up to 30 years in federal prison or $1,000,000 fine, or both.  

Should I send them the unlawful tenancy letter or just wait it out and see if they indeed leave on April 30th?.

Never accept excuses and punish when necessary.

If you are thinking about a forcible eviction, get the unlawful detainer and have the sheriff handle the case.

I am also familiar with the local eviction process, having filed an unlawful detainer in the past.The risk associated with picking up a 6 month balloon, high interest loan without knowing when I can start the work is quite clear.

That way you're not dealing with the unlawful detainer due to failure on the tenant to pay rent, but instead the tenant leases ended and needs to move out.

If you're really having problems finding a lender that knows this, it may simply be because Georgia doesn't have a particularly large immigrant population (I'm in CA, so this is normal for us - everything from Italians to Koreans to Mexicans).If you are in the country unlawfully but have an ITIN, you will need to search far and wide for an "ITIN Mortgage Lender."

That seems like a horribly unlawful, not to mention unethical thing for the landlord to have done. 

If you read all of that you must be a glutton for punishment lol.