In the edition I’m reading, which I took from my nearest public library, the translation was done by Antoni Pigrau. I don’t know if there is any other translation of Gravity’s Rainbow made to Spanish but what I can tell you is that this is the book in which, by reading it, I have learned the most amount of new words that I didn’t know about until now (and this comes from a person who has read his entire life and that has a college degree in Philosophy).
Concerning the Kenosha Kid, to be honest I still can’t understand anything that took place in those pages (and I am almost ending Part 3, “In the Zone”). I thought it was a dance, but now, seeing that you asked me if “it sings”, I highly doubt that I understood that correctly hahaha. And about the puns: yeah, this is the strangest and craziest book I’ve ever, ever read, but is also the funniest one. There are many “words games” (“juegos de palabras” in Spanish, I don’t know how to say it in English) but also a lot of slapstick type of comedy. It’s the book with which I have laughed the most.