To be honest, you simply can’t rearange, because you can’t move elements.
The only workaround would be to use for example a → multistate-box and create several possible scenarios different order and amount of buttons and then call the right state of the multistate-box.
If you also would like to see a new feauture in the velo-api, which would make a movement of elements possible, then take a look here…
…especialy here…
https://www.wix.com/velo/requested-feature/moving-elements-on-page