I just did a new game and finished it, for me Daphne did not show up.
Also more had been added to the "phoenix part" with some quest line, but i could only get to the part where i talked to hermione the #2 time about the polymorph juice but nothing after that - anybody else ?
Also finished the game, Daphne didn't show up for me either. But I went further with the Phoenix : when you ask Hermione about the phoenix, she tells you something about Hagrid at some point, then you have to ask Potter to go fetch a few Hagrid's hair, then Hermione will make a potion transforming you into Hagrid. When you have it you can click on the phoenix and there will be an option "drink potion" and then you can fuck the bird cause it thinks you are Hagrid. There is also more with Chow Chang too, but once you've fucked her with Snape (which happens quite fast) it seems there's nothing more to do with her.
About Daphne not showing, some infos if it's useful : I only used money cheats for most of the game, only used slytherin points cheat towards the very end. I also only used fiction books and did not buy any other books. And of course, new save.
