Can you add the starling helmet that gives handicraft and health to this?

It would be nice to have the +15 ring added to this fix if you have time. I got to say I find it a bit wired that Enderal devs are not able to fix this mistake, or at least provide instructions on how to solve it.

That command removes the buff when I put the amulet back on but doesn't fix the damage already done, when not wearing it. I just ended up using 'player.modav smithing 6' to put it back to +4 where it should be for my race instead of -2. Not graceful but it works.

Are you familiar with the console? Try this command: player.dispel 0101fe07

Unfortunately it didn't fix Hoofbeat for me. However its likely because I had already removed the necklace on my saves before realizing there was an issue. Putting it back on then doing all steps of your fix sadly didn't help. Thanks for trying though! :D