One question I would have to ask the op is that, Does Lethal Dose help I.probe? Or did they meant to say poisons? Kinda like experimental explosives.
I haven't yet tested Lethal Dose with Interrogation Probe. Testing crit chance is such a pain! I'd have to do hundreds of attacks before I was satisfied the test was statistically valid.
And the term "periodic effects" is so vague. Corrosive Dart and Grenade are clearly periodic. Interrogation Probe really is too, so I'd assume it should be impacted. But what about Orbital Strike? For that matter, what about Series of Shots or Suppressive Fire or Cull? An argument could be made that those are periodic, but I doubt they're included. But would I be surprised to find something working that shouldn't? Ha!