I know it will do great and its a great deal so it wont stay on the market for long.

I rebuilt my mom's house after it was destroyed by a gas explosion and fire. 

If your lender wont allow you the 2nd FHA loan I would have multiple people interested in the duplex you have in Des Moines.

I have other investment property that was destroyed and was cash flowing $800/month net.

The current owner also converted the living and dining rooms into additional bedrooms, effectively turning a 3bed/2bath into a 5bed/2bath to reduce the risk of big parties destroying the property.Can anyone point me in the right direction to make sure I don't close on a lemon?

If you have a storm destroy your roof and the insurance company says it was a 12 year old roof, they might say the roof was worth $4K less your deductible, here is $3K.  

The end returns wont even be close.

I always want to make sure, that if i need to sell property, that i wont loose money on it.

In their defense we did destroy the carpet between my dog and parties however he pointed out in a week both my and my neighbors water heater flooded our apartment twice so they needed to replace it anyway. 

Most, if not all of these wont pass (JUST MY GUESS)1031 exchanges mostly so.