I'm missing Connor's outfit, but I beat ACIII? What hell
That's not how it works.
It counts the number of UPlay-enabled Assassin's Creed games you've played. One gives you Altair, two gets Ezio, and three means you get Connor. If you only played AC2, then skipped to AC4, you'll only get Altair, in spite of only playing a game with Ezio as the main character. If you played AC2 and AC3, but no other games in the series, you'll have Altair and Ezio. If you played the original, AC2 and AC3, you'll ALSO only have Altair and Ezio, because the first game was pre-UPlay and doesn't count. If you played the Ezio trilogy - AC2, ACB and ACR - you'll get all three, even if you never played a game with Altair OR Connor as the main character.