Im having the same problem with the preview button so i make sure i close the tab everytime i preview a page so when i click preview again the changes i made are live. A terrible solution, i know.
Copyright is i think under Appearance >Generatepress
About the columns,the easiest is to use Toms plugin https://wordpress.org/plugins/lightweight-grid-columns/
Agressively support the kind of work you want to see. Buy it. Talk about it. Review it.