Scott,
So far the information you have given us, says to walk away from dually #1 (black and tan). That many miles on that new a truck with that many problems doesn't bode well for the post warranty ownership.
Dually #2 is a really nice looking truck from what the pictures show. I personally wouldn't go adding a complete lariat interior to that truck even for the price you can get it for. Even just adding the overhead console will require the purchase of a new wiring harness for the cab marker lights which is integrated into the same bundle of wires as the wires needed for the overhead console and the lighted sun visor mirrors (a lariat only option). Additionally, the Lariat heated seats will use a different harness than the one for a truck with only power seats in a XLT. Ford builds so many superdutys they can justify making all the different harness configurations to fit specific options in most trucks inside each trim level.
One example I came across recently, my brother just bought an 06 XLT supercab which did NOT come with the factory fog lights (it was an option for the XLT). He wanted to add the fog lights but just the harness would be somewhere north of $250. If you really, really want the bells and whistles of a lariat, let the green dually go to someone who wants a nice XLT dually and wait for a well optioned lariat. You obviously have some contacts that can give you an inside track that most of us would love to have when it comes to looking for a new ride.
Don't let yourself buy a truck just because it's in front of you right now. Ford outsells Chevy, Dodge, and GMC COMBINED 2 to 1, so there's plenty of trucks out there to choose from, be patient grasshopper, be patient.
Hope this helps.