Of course it does. That's what the last save is for, that starts right before attack on Cerberus HQ. But regardless where DLC takes place, _I_ do know how it all turns out. I doesn't delete all the info in my brain. So...
And if you think it is "gimmicky" to play with another character, then you won't like the next ME game at all. Current rumors say the next game will be with one of the surviving characters in the lead.
Yeah, good idea. Happens so often now that they probably just try to save marketing money that way. They must know that someone will see it if they leave it in files, so...