I did my research and no source said they were events. The only actual Dream World events that have been released are: Vaporeon, Flareon, Jolteon, Glaceon, Leafeon, Umbreon, Espeon, Bulbasaur, Charmander, Squirtle, Croagunk, Turtwig, Chimchar, Piplup, Treecko, Mudkip, Torchic, Arceus, Togekiss, Blissey, Mamoswine, Porygon, Banette, Altaria, Lucario, Burmy, Eevee, Smeargle, and Poliwhirl. Also any site that list events doesn't count any Dream World Pokemon besides the ones I listed.