Some questions about Assassins Creed 2 / II

Well, i was looking on the internet for some AC2 infos and found out that there is no Memory Sesquence 12 and 13, but also, there is 2 DLC for consoles (didn't see it for pc) and the especial editions says to have bonuses missions called "Templar Lairs"... And something curious, some people keeps saying that they only can get 97% of the game complete, why is this?

There go my questions: 1) About the sequences 12 and 13, what it is? Is there any way to play it? 2) The 2 DLC, "The Battle of Forlì" and "Bonfire of the Vanities", are they playable in pc? I have to download it? Is it on every edition of the pc version, or only in black/white editions? 3) The templar lairs are playable in the regular editions? 4) And the 97% com game completion, how to get it 100%?

The PC version will automatically have the DLCs. I was playing through the whole game then I read that memory sequence 12 and 13 were actually DLC's and I thought it was part of the whole game. The Templar Lairs are only available to those who had pre-ordered the game but I heard that it isn't much, just like entering the Assassin Tombs where you have guards around and platforms to climb and such.

Yes, they're integrated in the campaign.

I don't think the special edition tombs are in the game, but there's one that can be unlocked on the uplay site.