This article gives a very good explanation about the series.
tl;dr version: "There will be about 24 characters on the team in total. “By the time we get to 22 characters on the book, 12 are either female or minority"
People who are already confirmed.
- Captain America
- Iron Man
- Doctor Strange
- Black Bolt
- Black Panther
- Mr. Fantastic
People I think might be on the team.
- Nick Fury Sr. - I think it be kind of foolish to leave him out of the loop considering that Captain America is aware he's still active and after what happened with the skrulls
- Maria Hill - Current Director of S.H.I.E.L.D. She's already filled in on most things.
- Abigail Brand - Current Director of S.W.O.R.D. she's not as in the loop about stuff as Maria Hill, but she's more in the loop about everything that happens on earth involving aliens.
- Hank Pym - One of the smartest men on the planet and long time Avenger
- Bruce Banner - He's had much better relationships with the avengers recently and he's also one of the smartest men on the planet
- Sunspot - Probably the best rep for eastern super humans, and he's a mutants so it would be smart to have him around after what happened in AvX
- Blue Marvel - Probably the strongest person on earth and also one of the smartest people on the planet
- Vision, Jocasta, or Machine Man - With things like Ultron in the world it would be pretty smart to have a synthetic life form in the inner circle.
If he was still alive i could also see Richard Rider being a member because he's their best informant on what's going on cosmically, and unfortunately the new Nova is a kid.