Interesting. I'm now in a completely bizarre predicament.
1. I'm still unable to use the Evernote clipper in Firefox. Nothing I've tried has changed the behavior at all.
2. After using OneNote for a bit, I was surprised at how much better it was than when I first tried it. In my opinion, it's now so much better than Evernote, that switching to OneNote is a no-brainer.
3. Microsoft has a tool to import notes from Evernote into OneNote. It's officially no longer supported, and it's not perfect, but it works. What I hope is that if enough people petition Microsoft and express interest in switching, they'll reanimate the project.
Just a shout out, anyone reading this who hasn't fired up OneNote in a while, should take another look; it's a fairly amazing product and it's free.
4. I had not tried out Microsoft Edge until you mentioned it in your post. The Evernote clipper in Edge works for me. If I wanted to continue using Evernote, which I don't, switching to Edge would be an option. It's actually a very appealing browser.
5. Here's the insane thing. As far as I can tell, Microsoft has not produced a OneNote clipper for its own Edge browser.