Could swap S and W around and the connections would still work, so not a unique solution

Hmmmm, quite hard.

Oops. I did not realise the S version was a word! If I could edit it, I would, but it’s such an unusual word (I doubt many people playing the game would have heard of it), that I don’t think it’s too bad. Obviously, I chose W as a red herring on purpose.

Single-letter entries tend to be not much fun because there are just too many possible answers; makes it hard but not very entertaining. Liked the Bash Street Kids though