Given the fact that the ride has always had a Dia de los Muertos scene in it, a Coco overlay would obviously be expected. Still, I haven't gotten to see the animatronics yet, so I'd be a bit bummed.
Honestly, if IPs must keep infiltrating World Showcase, I'd prefer if they went with a style of ride where the culture/country is the main focus, but the various characters show up to enhance the experience rather than dominate it. We've discussed in some threads on the France pavilion that if they had to include Disney characters in a new ride, rather than just slapping on a Ratatouille theme, why not integrate a lot of the different French characters in the Disney catalog to help emphasize different parts of the cultural experience (e.g. Beauty and the Beast characters popping up in the provinces, a sweeping view of Notre Dame and the surrounding area of Paris, etc.), rather than making the culture come second to the characters from the film?
I mean, I do kind of understand it: why throw in multiple IPs on one ride if you feel you can get multiple attractions out of them elsewhere. But, again, it'd be nice to see corporate telling the Imagineers to make sure that each park in Florida really felt different and unique from one another, and not just like alternate Magic Kingdom locations.
On one other topic, if this does happen then I really hope they're NOT trying to cram in big crowds for it, for the reasons mentioned above. World Showcase works best in its current iteration with American Adventure serving as the big E ticket show, but with the other attractions sitting closer to C or D range. The infrastructure for longer lines simply isn't there right now, as best I can tell (and I'd be glad to be corrected on that). It was always why I was a little confused by earlier ideas to place a Mt. Fuji ride in the Japan pavilion, it's hard to see where the lines would fit well.
...Speaking of which, if the IP march must go on, could we at least get a ride exploring Japanese culture designed with help from the good people at Studio Ghibli? They just played Spirited Away in theaters for its 15th anniversary, and Princess Mononoke is playing in January for its 20th, so it's really on my mind at the moment.