Are ARP head bolts really needed for a mild build?

For what you're builing you should replace the bolts regardless. IMO, I would have studded the main caps too. You have more of a risk of cap walk than heads moving around. If you chose not to, do not use anything but straight 30wt oil, and make sure the holes are tapped and the threads on the bolts chased so the torque can be set properly. By using moly paste you run the risk of way overtorquing/stretching the bolts or distorting the hell out of the tops of the bores.