It's 12 developers + 5 additional contributors Rueckkoppler. Ed Bryan helps too, but has yet to be officially announced by Playtonic to join the team as a guest artist like Kevin Bayliss is. As for how many staff they'll need to become an "N64-sized" team that they've talked about on multiple occasions, is around 15 according to their Kickstarter of Yooka-Laylee. Anyway, this is great news! More ex-Rareware staff joining Playtonic, even one that had a hand in making Conker's Bad Fur Day! Awesome!