Although some of your conjecture doesn't fit with anything in the Marathon game, you've raised some very interesting points that really make a lot more sense than most of what we've bantered around in recent years. First of all, If you are suggesting that Bernard Strauss knew about the Pfhor and sought to use them for his own purposes, I don't think that there is any evidence to support that he even knew about the Pfhor - I think it's clear that it was Durandal who discovered their existence and summoned them to Tau Ceti:
i did it i did it i brought all this here all them here. our
friends with three eyes and their toys and their cyborg pets
and their computers. i did it i did it. i saw them i saw
them far away not looking our way and i called them here i
called them here.
That said, I agree that Bernard Strauss would not be satisfied to be surrounded by cyborgs and immortal AI's and to remain mortal himself - he almost certainly had plans for his own immortality - either by becoming a cyborg himself or even becoming an AI. I wonder if some of his own research might have been toward that end. Perhaps Durandal realized this, too, and this was one of his motivations to get out from under Strauss' control.
The other amazing point you made is that Durandal could have known about the closure of the universe before the Pfhor attack. The portrayal from the game is that he figured it out in the midst of the attack, but rereading his discussions to that end, he just doesn't say when he actually did the calculations. It is quite possible - perhaps even very likley that he figured this out during the 300 year journey to Tau Ceti and that escape from the closure of the universe was indeed a major motivating factor for him instigating the Pfhor attack.
