The idea that Durandal had used the Security Officer (somehow) to call the Pfhor is a new one to me (in the way you described it; I wrote a thing where the SO inadvertently helped, but that's not quite the same).
I, too, suspect that Strauss had a direct hand in the SO's conversion and had at least some idea of what those Jjaro implants would do; however, I'm not sure if Durandal knew that the SO's neural implants were Jjaro in origin. You'd think he'd jump on that, but IIRC all his hints in M2 are focused on the SO being a battleroid. Nothing like 'you and the S'pht have more in common than you thought', or something.
(Durandal--or Thothandal, rather--is definitely aware by the end of Infinity, but that's an alternate timeline)
