Or it could be the Narnians…

No it couldn’t.

Firstly, the Narnians weren’t able to exit through the Wardrobe (or even grasp the concept of a Ward Robe), and secondly the Wardrobe in question was a single and specific Wardrobe.

Portals don’t just turn up randomly in any potential wardrobe in order that a varied parade of Mister Tumni* can come and clothe their little cloven hooves in someone else’s hole-filled socks. That would be silly.

*Yes, I know, I’m playing fast and loose, but the expression amused me