Fortune Scraps
The Fortune Scrap vendor is being kept so that people who already have scraps will always be able to trade them in. They don’t want to limit people to needing to turn their items in NOW or never be able to get the rewards, they want to leave it open so that people can always get the rewards at any time. Same reason why the vendors still have stuff like Molten weapons despite the fact that unless you already have a claim ticket, you’ll never be able to get one.
There is no way to get more Fortune Scraps right now, though.
Zephyr Sanctum will be a recurring event, but I don’t know if they’ll bring back Fortune Scraps again or create a new currency for the next time around. You could save them just in case, though.
You can buy the Catcher skins off the Trading Post if you want them that badly, so you aren’t completely out of luck there. The only things that are only available from the Scrap Vendor were the helmets.
You could also exchange the scraps for Zephyr Supply Boxes, which have a rare chance to contain a Kite Fortune. Those in turn can drop more scraps or a Golden Fortune Ticket. Of course, this is basically a “last ditch gamble”, so if you’d rather not risk it, you can just wait until the Zephyr Sanctum returns and hope that the skins are still available.