Have you thought about a Holley HP system for the wiring? It'll save yourself a heck of a lot of headaches. It would make it a lot more user-friendly you could tune it with a laptop or Buy digital dash if you wanted to spend the extra dough.
I am presently researching multiple options on that front. I have a buddy who is a Holley distributor. I am also looking at Mega squirt and Hot wire auto out of ark. I fear I will have no choice but to go to a digital Dakota style dash.
Everything I am reading says the OEM dash is not happy when not in OEM car with all associated inputs. Using the OEM brain box even with a reflash to reduce fault codes creates issues with the OEM dash. Since I have to fabricate my own dash anyway I may just bite the bullet and go with Dakota.
I have a Dakota in my Cuda and it was smooth to install, in fact it was painless. Hah! Seriously I love the Dakota Dash in my Cuda, it looks great and I have had zero issues with it and the car gets thrashed regularly.