Well I can answer the first part. The second part I don't honestly know.
Ok when you reach a little higher level your memory of the past becomes much stronger all your past lives your past in this life etc plus you are able to pretty easily sense what the future is too. It all exists at the same time. Someone highly competent in this would just know they might see how all three are connected together and they are kind of all the same the present.
Sensing the future only becomes difficult when a bunch of wildcards are thrown in there and random things. It's pretty easy to project a straight line maybe many here can do that however if a bunch of people are consistently changing what they are doing or like in your life or you keep doing that chances are what you sense won't happen.
This is my experience. Prediction of the future appears to go in a line kind of way but that's not really how the future goes. If someone changes path in some way they change the future.
Let's say as an example you know your going to get into an accident around a certain time. You do not drive or ride with someone on any of the days that fit what you see.
It doesn't happen. This is what I mean by the future isn't written in stone.