I haven't watched interviews, and so I was just going off what I saw onscreen. To me, it wasn't clear the guy was dead, but fair enough. He wasn't working alone, I assume, so there are likely others who could weigh in on what was happening.
It doesn't matter. The movie establishes that Lois was successful. In terms of the movie's own internal logic--messed up as you may think it is--she succeeded in clearing Superman's name. That matters in terms of how we judge her. We can't say a character didn't accomplish something when the script tells us that he or she did. You can argue that it wasn't believable to you, but you can't argue that it didn't happen. If it happened, then Lois' accomplishments are real in the context of the film. If you don't buy it, that's fine. It doesn't make it true that Lois' investigation was pointless and she herself was useless, though.
I don't get you. On the one hand, you tell me what the film states doesn't matter with regard to Lois' investigation successfully proving Lex's conspiracy to frame Superman. On the other hand, you're telling me that the film states something about the General so it has to be true and unchanged even though the end of the movie tells us that Lois had proved her suspicions correct. You're assuming that the extraordinary circumstances wouldn't have allowed for the information to be revealed or that the General wouldn't have enough courage, especially after the tragedy at the capitol, to put his own neck on the line for truth and justice. The fact remains that the script tells us that it was all proven in the end, making your straw grasping to delegitimize that truth and the accomplishment that comes from that reality seem incredibly unfair to Lois.
Yet, she accomplished them. Whether you buy it or not, it doesn't matter when it comes to what the movie establishes as her contribution.
You can't substantiate what you're alleging either.
I would have loved her to be utilized more and for more of the dots to have been connected on screen, but you don't have to go a step further to dismiss what the movie did establish in terms of her accomplishment. At the very least, you could frame your critique more accurately as there needed to be more to support the plot's conclusion rather than what it seems like you're doing, which is to deny even what the script states that she accomplished.