The problem isn’t knowing your future. The problem is remembering it like it’s happening to you and being physically changed by it. But no, not everyone knows what their future holds for them magically or otherwise.
We don’t know. It has something to do with being displaced. Like we’re existing on two different timelines/locations at once and occasionally we synch up with what happens to us in our normal timeline.
I’d prefer if you didn’t tell anyone about the potion yet. There may be people who want it and until we know we have something safe and effective - not to mention we don’t know how many doses we’ll even be able to make - I don’t think it should be advertised.