I don’t think that Rumpel knew that Emma would kiss Henry and that it would return everyone’s memories and i don’t think he cared about that at all. I see no reason that he would care about any of those things because it is not helpful to him. He did need Emma to believe so that she would help him and i think he reasoned that that would eventually lead to other people regaining their memories, but i see no evidence that he cared about Henry being saved or the timing of people regaining their memories. And i don’t think it makes sense that he would care based on what we know about the character so far.