Today I got that comic. It was an okay story, and would be willing to exchange an episode somewhere along the way for its inclusion, but at the same time, it wasn't anything great, IMO. (Also, the description on the back of it is strongly misleading.)
Some who don't hate Dawn might after they see what she says to Buffy in one scene. And it sure adds to the mystery of why Buffy won't kill Harmony (I'd say because Harmony makes her laugh, but if she's so worried about her sister...). Again, it was okay, but nothing special.
The false memories are incidental, and just shown in flashback forms. It would appear she found out about Buffy when she followed Buffy when she went to face the Master (who completely ignored Dawn even when Dawn screamed a warning to Buffy, and it was Dawn to say use CPR), did not handle Xandelia (Candor) well at all, was the first choice of Angelus to go after. I was hoping to see why she hated Faith so much, but Faith isn't shown at all, and I don't remember her being mentioned.
'Course it's irrelevant since the flashbacks never actually happened, similar to how Jonathan didn't really do all those things in Superstar. That's why I can overlook the Master ignoring Dawn, etc. I could headcanon it to say that the monks added in memories of a mental hospital, both to keep Dawn (who typically sticks with Buffy) away from those who can see her as the Key (as it might remind Buffy of what happened) but that Dawn didn't want the same thing to happen to her...or to Buffy again.
Amazingly, Joyce did not show up at all, I don't think even in flashback, though she's mentioned as being in the hospital. But I did like that Dawn has Mr. Gordo now.