I agree that this became a great technical discussion. Thanks for moving it!
If wire brushing removed that coating it definitely did not have good adhesion.
There is minimal risk using those bolts. The big variable that we tried to control in bolted joints was the coefficient of friction between the threads and under the bolt head. Different coatings and platings plus the presence or absence of a lubricant change that coefficient. If the coefficient is high it takes more torque to produce the same clamp load. If it is low you can overload the bolt in tension.
Just do the oil thing and tighten the bolts in stages as discussed. I do not know if the head gasket you are using requires that the head bolts be re-torqued after some use. Follow whatever instructions came with the gasket.
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