I have accomplished all the achievements but 1. I forgot to talk to Lucy the first two nights. When I go back to play those memory blocks it doesn't let me talk to her after the assassinations. Can you do this without starting over?

to do anything outside the animus after finnishing you need to restart.

i've got a Q for you. after finishing the game, can you replay a memory without having to watch the credits again, if so, how? it wont let me replay a memory until after i look at the bedroom wall to finish the game. then i have to watch the credits all over again, which takes forever, just so i can go back and replay a memory. Mad

I seem to remember that after you've watched the credits, if you go into the animus and replay a memory, and then get the game to autosave (by finding a flag/viewpoint/templar etc), when you quit and next go on the game you wont have to watch the credits again. I could be wrong though, so don't take my word for it.