Zapdos vs Raikou? Moltres vs Entei?

Why not wait until you actually acquire one? I doubt people will have all the Legendaries next week.

I think that the 3 dogs, Mew and Mewtwo won't be in this month's legendary/mythical egg rotation, and will first be available for the next event. Like this event will be the release of the 3 legendaries birds and 2 mythical Ho-oh and Lugia, and the next rotation will bring us the dogs Mew and Mewtwo. Just a thought..

Zapdos has more resistances (6) but one more susceptibility than Raikou.

It will still probably come down to moveset and IVs when making that choice--if you're lucky to have it.

Is it even possible that everyone can get all of the team specific birds, or only your color? That is, can I catch a Zapdos if I'm not yellow?
Does anyone know?

Even though neither is released, just by going off of movesets Raikou wins easily. Zapdos has CHARGE BEAM as it's only quick move. CHARGE BEAM. Charge Beam is literally garbage, and so are most Electric moves in comparison. Thunder Shock should at least be in line with Water Gun, but instead it does the same damage and takes longer. And Volt Switch? Jesus Christ let's not get started on Volt Switch compared to Confusion. Niantic seriously needs to adjust Electric moves, being blatantly bad like that is just ridiculous. EDIT: I was so bothered by Electric moves I forgot the second part of the question. I'd say it's safe to say Entei wins, even with slightly lower attack he'll do more damage in the long run because of his bulk.