Not the most convincing rumor I've read so far, but definitely one of the more amusing ones:
http://makingstarwars.net/2015/06/is-wicket-in-star-wars-the-force-awakens/
The real question is, would Wicket still be around 30 years later. I always imaged Ewoks would age in dog years or something similar. Or are they like Wookies that live for freaking centuries.
I never really understood that aspect of sci-fi, why does everything non-human always live for so long?