Can I play Assassin's Creed 2 or use Ubisoft's Uplay offline?

Ubisoft never removed the DRM, they just made it less harsh if you get disconnected. It's still just as harsh on not being able to play while not connected.

All the updated did was basically, instead of quitting the game when you get disconnected, forcing you to restart from last checkpoint, it now pauses the game until you get connection back, which means you restart from the exact same point. If you quit instead of waiting to reconnect however, then you must restart from the previous checkpoint as before.