To rearrange the order of the thumbnails in your Favorites, simply go to your Favorites page and enter Edit Mode for your gallery by selecting the "Edit Page" button near the top right of the page.
An "Edit Your Gallery" banner will then appear near the top of the page. You can then drag-and-drop any thumbnails you please, in the Favorites section as well as in the All section. To move a deviation to a different page of your Favorites, drag the desired thumbnail down to the bottom of the Favorites page and drop it on the desired page number, which will move it to the top of that particular page.
Your Favourites page consists of two main sections -- Featured and All. All deviations you add to your Favorites will show in All and are, by default, added to the Featured section as well. The only exception to this is if you add it directly to a Collection Folder, in which case it will go into that folder and the All section, but not the Featured section.
Since it is your Favourites, you can decide what to highlight in the Featured section. You can add any deviation from the All section by entering Edit Mode, hovering over a thumbnail there, clicking the pencil icon and using the "Copy to...' in the menu to add it to the Featured section (or any of your Collection Folders).
Conversely, you can remove any deviation from the Featured section by entering Edit mode, hovering over a thumbnail there, clicking the Pencil Icon and using the "Remove from This Folder" action or the "Move to... in order to move it to another Collection folder.