If you paid all cash you didn't even have to wait the 6 month seasoning period you could have in theory done it the day after if you would have liked.

Also instead of locking up a bunch of money doing a brrrr wouldn't i be able to buy multiple homes in that time period by putting 20% down?

If it isn't too far out of your way, you will probably feel better if you check on it periodically (with his permission). 

Is this standard for a property to drop in value over 100k over a 15 year period? 

If staying in a motel for a period of time doesn't bother them, they have low standards. 

Recently applied for a loan and was denied based on credit score.I have never had a credit card and the only thing affecting my credit score are some old medical bills.Any ways I can build my credit in a short period of time without getting a credit card?

There will be a lock period up front where the interest rate won't change, and that can range anywhere from 1 - 10 years. 

Also rent must be paid in poems now, no more US dollars, and there is a 4 year arbitration period before you can evict for nonpayment.

There is no statutory holding period. 

I don't think you screwed yourself, you're in the middle of a growth period.