Squirrel Luann

The outfit stays in your inventory. So when you do get her you can just click on it and it will unlock.

The skin goes into your inventory until you get the character.

I have this situation with the Captain Bob skin from the Homerpalooza event. Since I don't have the character, the skin for the character is stuck in storage until you get said character.

(In my situation, I'm at the mercy of the RNG God. In the situation with Luann; you need to shell out the Sprinkles to get her.)

I had this issue when I won her last year. Finally managed to buy Luann a couple of months later and her squirrel skin is now one of my favourite in the game so it wasn't a wasted win at all for me :)

(Still got a couple of Stonecutters skins and Christmas house skins in my inventory from way back when!)