I would contact M&H directly and tell them EXACTLY what you plan on running under the hood and see if they could build you one with the accessories you plan on using.
You can talk to M & H about harnesses but they won't sell to the public direct; something to do about exclusively selling to certain vendors like Year One.
Now, correct battery cables - they will sell direct to the public. They do have all the drawings for the different year cables. I bought a positive and negative cable set from them for my 65 Barracuda and it was spot on. I believe Ulf also bought one for his award-winning 65 DartCharger which was also identical to OEM.