I still don't think it was. I mean.. I think it was something sent to look like her, with her memories etc. It wasnt 'literally' her but, if you will, a clone of her. Much like I don't think it was actually Cordy that came back in "You're Welcome"maybe that's why the Powers felt generous and sent her to her son in season 4.
I doubt that. If they wanted they could have just given the vision to Angel, but they needed to make sure he was accepting and willing to believe it and find the motivation behind it to sacrifice himself and his team. They used Cordy's image as the Apple Juice that makes it easier for the kids to drink their medicine.if only because they still needed to kiss to transfer the vision
Jasmine was a lier per se, she deceived people all the time. She also told that Angel and the others made that illusion, which was not true. So it is more likely she lied to Conner and it was real Darlas Ghost sent to Connor by the Powers that Be. I assume that from how she behaved, she was redeemed for her self-less act to protect her child.That could be a possibility with Darla actually. I don't think so with Cordelia (if only because they still needed to kiss to transfer the vision), but I think Jasmine did actually suggest to Conner that Darla was just an illusion. I mean sure, she didn't want him listening to her, but I guess that doesn't necessarily mean she was lying about that bit.