As far as 180 goes (I was really hoping you weren't going to ask) would be OK, go over it with 320 again, just to knock the high points of the 180 foot print off. The reason I cringe at 180 is I don't know how well your epoxy fills and 180 leaves some deep scratches and when primer fills these scratches it has a tendency to shrink in time and the scratches show up sometimes 4 to 6 months down the road. Also allow extra flash time before giving it the second coat to get as much solvent out of the primer as possible. This will minimize chances of shrinking later. I know your primer is 1 part primer 1 part catalyst but you still have solvents in the product.
Make sure you go over it again with 320, it's a bigger jump in grit than I like but your re-priming so all should be good.