If you want to make Superman, Superman II and Superman Returns, you could always re-edit Superman so that the movie ends how they originally planned it--he catches the nuke, throws it into space, and ta-da. Then Superman II can end with the world turning back, and Superman Returns can continue.
OR: You can just leave the world turning back in Superman II. Superman Returns still follows perfectly, check this out: Just because time has turned back doesn't mean Lois is no longer pregnant. In the silly version of "turning back time" that happens in this film universe--everything goes backwards, but Superman. Otherwise, when he was done, there'd be an additional Superman there on earth. So since Super-sperm can't jump out of Lois and back into Superman--the kid is STILL IN THERE after he reverses time all the way back to the end of Superman I. He leaves, she gets pissy, hooks up with Richard, and the kid that was already inside her, she just ASSUMES it's his.
OR: You can just leave Lois on the balcony, and Superman trusts her. And then he leaves, she feels betrayed, and finds a man rather quickly, and convinces herself that he's the father, not Superman. That makes interpreting Lois' actions part of the scheme, though, because then her "act" that she doesn't remember Clark is an act, indeed, for the public. That might be too much of a stretch though.
But I don't understand why you NEED the magic kiss if you're going to try and link Superman II to Superman Returns. Since Donner has moved Lois and Clark's sex scene to before he depowers, and then runs the world backwards, reversing everything BUT the fact he has his stuff in her, due to the rules of time travel in the film, she's still pregnant and doesn't know he's Superman. That sets up Superman Returns pretty perfectly. AND, Donner even hints in his cut that Lois MIGHT get an inkling, later. Which she does--and it all might come flooding back to her in the sequence where she leans over and whispers to him what's up. She remembers it all, finally, even if it didn't happen anymore after he turned the world back.
The Donner Cut ending to Superman II seems to fit in the continuity of Superman II better than the magic kiss does, if you look at it that way.