You can change the keyboard shortcuts using the Tile Tabs WE Options dialog. When Firefox 66.0 is released, you will also be able to change the keyboard shortcuts from the 'Tools > Add-ons' page.

You can synchronize scroll adjacent tabs if you enable the 'Sync Scroll' menu item on the toolbar button menu or the page context menu. When you scroll any tile in a horizontal or vertical group of tiles, the adjacent tiles will also be scrolled.