Theory 3: external interventions - Flashforward and time travel theories

This post is part of a series about flashforward and time travel theories. Might contain spoiler. Please start reading here.

Theory 3: external interventions

Ok, theory 2 seems to go along with Mark investigation and some events in the flashforward, but has been invalidated by Al's death. In particular this goes against assumption 2:

• A specific "possible world" setting, without any external intervention (par example people causing flash forwards), the future is fixed: starting from the same exact variables events will always evolve in the same way.

What if we theorize a world as depicted in theory 2 (the flashforward shows a future where the flashforward itself is taken into account) and add an "external intervention" ?

Figure 4: a new timeline "manipulated" by a further external intervention.

But what could cause such an external intervention? Who? Here we can start with a lot more theories, but let's start with a simple one: there is a group of people "behind" the global blackout and the flashforward. They have instruments (or powers) that caused this event, and maybe can interfere with the normal time flow in other ways. For example they could cause flashforwards to a controlled number of people (maybe themself?) and act according to the future they see.
One of their intervention could be the attack against the fbi agents.

Good points:
This theory would explain both the fact that the flashforward is "implied" in people vision and the fact that some events (Al's death) made some vision "impossible".  It is also possible to find a specific event explaining two changes in the future: the attack against Janis. Janis ends up wounded and it will probably be impossible for her to have a child (invalidating what she saw in her flashforward). By the attack the "Blue hand" investigation starts, Al knows about ghosts and their dispair, and decides to kill himself (invalidating his and Fiona's flashforward).

Problems:

The problem of how people are acting at flahsforward time remains unsolved.
A new problem is introduced: how can those people "intervene" and change the future? Why their intervention is not considered in the blackout vision?

Addressing the problems:

We know very few of how the blackout was caused but we can assume that people that caused the blackout have the power to "change the future".  However this theory does not add any clue on the reason for the "strange" actions at flashforward time.