Someone correct me if I'm wrong, but one of the main reasons I remember for the Scots to remain in the UK during their recent referendum is that they didn't want to end up leaving the EU. Must be a big kick in the nuts for them if this goes through.
Just buy a stripped lower and deal with the rest later. That's the only part that's technically considered a firearm by the feds anyway. Even with an AR-15 ban, you'll be fine to complete your build at your continued molasses pace.
I feel like I've been hearing about this AR-15 of yours for years. You're telling me you haven't managed to cobble together one by now? You could have fabricated one by hand at this point with all the time you've taken deciding on parts.
I've been on the hunt for a Marshall in the box pedal lately. I just played a friend's Marshall DSL40c with an upgraded speaker (Creamback I think), and well, looks like I'll just go for the amp instead. That's the sound I've been searching for so no reason to settle for half measures.