That sounds interesting for sure, but from previous experience it's highly unlikely that they'll do that (change the pokemon's colour). It has never been done before. Also, I think that it's really hard to do that. On the other hand, it would be possible to add some Easter particles, maybe even some limited or seasonal vanities, but I think that event is not happening. I think so because I think that Kyu said somewhere that having 3 events a year is maybe too much (I might be wrong tho). But catching some wild exeggcute with particles would be fun for sure.