Lower eyelid retraction/negative vector - what might be the best option to fix this? (photos)

The word "best" is alwyas in the eye of the beholder. Your main thing is that you need to build up volume lower than your lid so that you hav less of the negative vector and have more support to your lower lid. Most likely by doing that alone, you can save yourself from getting a canthoplasty/pexy. To achieve that, you could consider malar implants, filler, fat grafting, midface lift, possibly a combination of the above.