One thing about libel that many people don't understand is that retraction and editing of the content isn't a defense. So where it says "note the libel-friendly phrasing" and "now edited to avoid any possible threats of libel" and "[editor’s note: removed a possibly incorrect claim]" he could still be found guilty of libel if previously published assertions contained non "libel-friendly" phrasing. As long as a defamatory assertion was published at some point, you can still be found guilty of libel.
It probably goes without saying, but it is also not a defense to libel to say that you asserted something to be true merely because there was no evidence to the contrary. Absent a contractual or legal obligation, Lumina had no duty to engage with him and answer his questions. So if Lumina can provide evidence that Trevor asserted things that are demonstrably false, and they damaged Lumina's business, then Trevor can't argue as a defense that he merely had no way of knowing that they were false.
Finally, Trevor seems to be saying in his update that he was merely asking questions -- but it's possible for a court to find that merely phrasing false, defamatory assertions in the form of a question is not an absolute protection against a libel claim.