Glad to help. Not a pain at all.
I really don't understand why they told you to use epoxy primer. I have used urethane primer a LOT on bare metal and NEVER had a problem. I may get people that don't agree, but if the bare metal is clean (I use #15230 Martin Senour wax and grease remover) I have not had a problem. Your alcohol may have bitten into your filler. I really don't know. Mix up a dab of your filler on a scrap piece and see what happens. I use an etch primer on aluminum for adhesion but only use it on metal if it is something (like a bike frame) that might get chipped or banged around during assembly. I have never used an epoxy primer therefore I have never had a chance to screw it up. Had I ever used it I probably would have and could tell you more about it. Any decent painter has screwed up a bunch. I will tell you what I would do now, but without seeing this deal this is tough to call. I would let the whole deal dry completely. Sand out the problems. If your sold on the epoxy put filler on a scrap panel and shoot a small spot. What I would not do is use alcohol to clean the panel. If you don't have a problem go ahead and shoot it. If you do have a problem with the test panel go ahead and shoot the job, urethane over bare metal and filler. You've worked hard on it. I really hope it turns out nice for you. Persistence will pay off.