Rogin

*waves back* You're right-- "he doesn't know yet" could refer to Fred's return/existence, Illyria being alive, or even both. At the beginning of his scene in "heaven" with Fred, he says something to the tune of "so you WERE in there" (Fred was existing in Illyria). Not-Fred says "maybe a smidge" in agreement. Perhaps Wes thought Fred was in Illyria, and it was Illyria's death in the battle that released her. Then again, Not-Fred says that it wasn't heaven for a few months, until Wes got there with her. This implies that "Fred" was already in "heaven" from the time she died. A contradiction? Did Wes catch it? If Wes believes that Fred can't exist unless Illyria is dead, and Fred is the carrot that they are dangling in front of him, the SPs (or mystery villains making him think they are the SPs) sure aren't going to want him to know that Illyria is still around. Despite what Wes may say, I do think he believes Fred is in the afterlife, and he may get his reward. Note his excitement and hope when Lorne's messengers show up for Angel, and he thinks they may be for him, so he can move on.

Or... on the flip side, the actual Fred coming back is part of their plan, they just didn't want Wes to know too soon. Maybe they even were the ones who brought Fred back (the fire circle on the ground implies a spell of some kind). I do think that the gaining of Illyria's power could be the end goal. She is very powerful (maybe, like you said, as powerful as she was pre-drain, but doesn't have control yet) and surprisingly vulnerable and easy to manipulate at times. (My pet theory about Knox, for instance, is that he didn't resurrect Illyria because he worshiped her, but because he wanted to use her power). Fred's resurrection could have been done to stabilize her powers, or to drive her over the edge, or to bring her even closer to their "key", Wes.