Collectibles are arranged by dates, oldest ones being in the bottom right of your lineup and newest ones being in the top left. To have one of your mittens on the left side it would have to be dated AFTER the blue rose, which is dated 7-22-2018 06:19 AM. Mittens with a date that would fit your lineup do not currently exist, otherwise i would say you could trade dates.
The only issue with this is that it can be difficult to trade fates for collectibles that aren't really in circulation or are one-time things (like fair and event collectibles). It would be nice if we could simply change them atound, but it always feels good to go through the process of trading and actually come out with the lineup you want