I didn't find anything about Chucklefish plushies when i did some research. But if there is no shop for chucklefish products i would probably send a enquiry or maybe even shoot them an email and ask if they have anything planned along those lines. I would probably look at fan made ones if there are any, I've seen fans make Dango plushies for those who loved the Clannad anime and even make plushies for Youtubers like Vinesauce for example.
the old spiked one would be cool, but the current one is just a baloon with face and fins but if they ever make one it should be squeezable and make the chuckle sound when beeing squeezed.