Wicked as They Come discussion

Okay, so recently I read Carniepunk, an anthology that Delilah S. Dawson wrote a Blud short story in (it was called "The Three Lives of Lydia"). This story explained the romance between Lydia the Tattooed Lady and Charlie, a Bludman, and I absolutely loved it. While I'm not quite so fond of Criminy, I kind of want to give the series a try, but the whole reason I got hooked was due to the whole Charlie + Lydia romance. So my question is, for any of you who have read the series and can answer it, do Charlie and Lydia ever show up in the main series? Or are they just some sideshow? Because I'd really love to read more about them, but I don't want to comb through the books just searching for parts about them if they are only minor characters.

I don't remember Lydia and Charlie mentioned much in the first book, if at all, honestly. Perhaps they play bigger roles later in the series. Probably not though, since they are the MCs in a novella.