While checking out my camper today. The camper was Katt. I LOVE KATT. (I know she gets a lot of hate but I don't care.) If my town wasn't full I most likely would invite her into my town. Sadly I just can't make someone move.
I love Katt too. I see her being given away a lot in the Villager Trading Plaza (that's how I got mine), so keep your eyes open once you have a vacancy.
I love Katt as well; hopefully, she'll show up in your town again soon. If you want to go far enough, you can see if anyone here on the Forums would be willing to give her to you.
I love Katt too and was lucky enough to get her recently! I'm facing a similar problem right now, with someone giving away one of my dreamies but my town is full and I'm trying hard to get the villagers to move.
I think Katt gets given away with some frequence judging by the searches I ran when I was looking for her, so don't give up hope!
Octvian was in my campsite today... Full town.
I don't like him or anything and already have my dream villagers, but if I had the space I totally would have let him in since I know people like the octpi villagers.
Awww man I totally feel you. I had the same issue when Tia was camping at my town twice while I was full. And I LOVE Tia. Thankfully, kind people here at TBT are willing to give her to me for free ( after I have room for her) good luck finding Katt! I'm sure you will succeed in no time!
ahh my baby katt <33 ive noticed shes actually quite popular, just "underground" popular, and even though lots of people want her shes always given away for free bc most people assume no one wants her.
I posted on a thread about her saying I wish I could get her, and then someone asked me if I still wanted katt and someone was nice enough to hold her for me while I cycled out a villager. good luck getting her hon!! (if youre like actually planning to seek her out)
Good thing I never had this problem. 
