Lisa - We can access other lives in the Records and bring skills, resources, wisdom into now, just like we can send those things back towards the other lives. It's a symbiotic link. But I'm also referring to simple, meditative moments when we're so present that our chattering mind steps aside and our wisdom finally has a chance to shine through. Which can bring us to the constant state of accepting ourselves in the moment (enlightenment), which allows us access to all the lifetimes so that we can use that wisdom now.
Ssandra - Just to be clear - time itself is linear. We perceive the mental concept of time as linear. Reincarnation itself is non-linear (so far as time frames), but builds onto itself in a progressive fashion. In the micro perspective, we incarnate from life to life in a non-linear fashion which feels progressive to us. In the macro perspective, lifetimes are simultaneous.

I know it can be confusing!
I've used the analogy on this thread of watching a movie where we see it in a linear sequence, but it was actually filmed at different times and spliced together. The beginning of our film (our career of lifetimes) could have been filmed last in a linear time perspective (i.e. first life in the 2367), where the end of the film could have been filmed earlier (last life in India in 500 BC). Once we're watching the movie, we see how each scene (life) builds onto the next - it doesn't really matter 'when' the scene was shot - it looks whole and complete. The macro perspective, is that our lives are like radio or tv stations - in reality, they are playing all at the same time, just a different frequency, but we simply select the one we want to watch in the moment. Like watching a movie dvd - we can watch each moment build onto the next one in a linear fashion (micro view), or we can access any moment of the film (macro view).
Time is more of an imposed, social concept than a reality. For example, if you took off in a space shuttle at 11am Eastern and it took an hour to reach space, what time would it be? To your body it might feel like lunchtime, because of the cycles that you are familiar with. But in space you don't have a 'time zone' per se.
Let me find another analogy that might help. Think of our planet, in this timeframe, like a certain university. There are people who have been on the planet a long time, meaning they have come to the end of their cycle of lifetimes, and are ready to graduate to the next greatest adventure (graduating seniors - some people might call them 'old souls'). There are some people who might be having a tough time because it's their first life here (freshman), at least from the micro perspective. There are people who have graduated and stayed to help others as teachers (enlightened masters, ascended masters, etc). There are people who are here to build onto their existing 'education' (Master's students), and there will be those that continue on to further education (PhD students) in another timeframe. In this case, think of the 'past' and 'future' as more like another college in another place - Australia, Europe, America.
We ourselves setup the basic parameters of life and then come into an incarnation to respond at the greatest level we can. It's like we setup the amusement park (life on Earth), then select the certain rides (the self-selecting process of incarnation), then respond to the ride (we love the thrill of it, we feel scared, we laugh, etc). We've chosen the overall number of lives, and the order of lifetimes becomes self-selected based on where our next greatest adventure in consciousness is. Once we're in the life, then we play out the various immutable events that we ourselves placed in that life, trying to respond with the greatest level of consciousness, so that we live in the best of circumstances.
So back to our friend whose next life is in the past. Although we might be able to read historically about this person now, he has yet to live that life. And as he lives that life, some of the 'facts' that we know now, might change. I know, it can be kind of strange to grasp this, especially if it rubs up against what we've learned.