I still don’t think that Rumpel can see the future. If he made the curse then he caused it to happen and gave it to Regina and helped her to enact it. He collected ingredients and told her about using the heart of the one you love most. Rumpel caused the curse to happen so there is no reason for him to have seen the future. It is sort of like if i tell you that i am going to hit you and then hit you i didn’t see the future i just made my statement come true.