As for the new eeveelution I personally think it's a flying type, the ribbons and the kites as its all been said so why repeat it...
As for the forever speculated "light type" I do see where people are coming from really, I mean it's extremely happy looking as a pokemon- you'd things that represent good and light would be happy. There's also a lot of fabulous sparkles surrounding it, this could just be representing its 'newness' but maybe actually representing the light type, and again the ideas of goodness and purity?
Also it's on it's tip-toes on its feet things suggesting it is a light, nimble dancing pokemon... Which actually makes me more think of flying if it's light and nimble and the ribbons are a frequently used dancing prop...? Maybe it doesn't even fly and it's the nimble and light nature that allows this?
Another thing that I had a small thought on... Could it be dragon? Tenuous I know but the repetition of the blue and pinks could actually make it dragon? I mean I don't know I get a slight dragon vibe, but there's a seeming lack of scales or reptilian features... Then again maybe it breaks the mould?
I think the fact GF are retaining the typing is probably just to create media hype tbh but eh well it's working.. We'll find out eventually!
As for #666 I think a small reference would be nice wouldn't it? I mean just because its amusing for people that the idea of heaven and hell are thought of in the PKM world.. I mean we had a cathedral thing in Sinnoh...