The simple answer to stay out of any kind of future trouble is No. We would not recommend taking any rules from a future new version of Pega and move/import into an older version to avoid any incompatibility issues. It is best to stay with the recommended product stack to ensure continued Product Support from Pega.
If there is a specific feature of UI Kit 10 that you'd like to use in 7.2.2, let us know and we can check if there is a possibility of delivering the same functionality into 7.2.2.
The multi-select was built in Pega 7.3.1. Using a newer version of uikit won't get you that feature as that feature is built into our core Pega platform. I just spent a few minutes digging around in our platform and it looks like, with all the rules involved, it would be a lot of work to backport that feature to 7.2.2
I'd recommend using the list to list control until it's time for you to upgrade to a newer release.