I've never heard of the butter trick. However, if you're moving your furniture and all of the cat "stuff" like litter boxes, food bowls, toys, etc, there should be enough familiar smells to settle them in. We drove 600+ miles to rehome our cat. After not seeing "her" rocking chair for a few months, she settled right in as if nothing had changed.
Good luck with the move and your cats.
"Let things taste of what they are." ~ Alice Waters