According to Gossip Cop, the rumor that Megan Fox's character will be killed off is "not true". Sadly the exact quote was not provided.
As I said before, this rumor should be taken with a grain of salt as I doubt so much as a single line of dialogue has been written so any conclusions on what may or may not happen to her character has probably not even been discussed in any great depth. Now if this rumor re-emerges after a known draft of the script circulates, then that is a whole different animal. Realistically, any casting or script rumors for the next few months should not be taken at face value as a complete first draft is probably not due until the beginning of next year.