In books that go through multiple editions, you will sometimes see "preface to the first edition", "preface to the second edition", etc. In other words, there is precedent for not editing it out but instead adding to it, even if -- for all we know -- the stuff people helped with in the first edition has since been removed. Your original novel had help from people on both plot and language and you thanked them; you've now taken that work farther and have more people to thank. That doesn't mean the first people are no longer relevant. Even if some of them only helped you with Spanish issues, could that work have then helped produce a better English translation (by having a better baseline)? Possibly. So their contributions might not be so irrelevant after all.
Further, it costs you very little to thank people and, potentially, quite a bit to decline to thank people by editing them out of the new edition. I assume you want to stay on good terms with them and might want their help with future novels, so erring on the side of too much rather than too little when it comes to thanking people is a good idea.
So I would recommend something like the following:
I would like to thank Alice, Bob, and Carol for their feedback on the earlier (Spanish) edition of this book, and Dan, Emma, and Frank for their feedback on this English translation.
Don't ascribe credit to Alic/Bob/Carol for work they didn't do on the English version, but don't leave them out either.