Considering the movies takes it cues from the comics and the various TV series... SPECULATION What if the new movie has some time travel involved (we've seen Jetfire's teleporting abilities so it may not be stretch), and what if bumblebee doesn't die but gets "lost" in some time travel mishap via sacrifice or something in the end of the movie. The spin-off will be one of those "hearts of steel" inspiration with Bumblebee in Earth's past.
I honestly don't think this movie has any time travel. Just flashbacks and whatnot. As for Bee's fate, I firmly believe he isn't dying. If he does die, then he'll be revived and rebuilt into a stronger body that's more fit for a leader, like Goldbug.
The bumblebee movie, I get the feeling will be mostly a right of passage movie....how bee takes over from Optimus as leader of the autobots....just a mention though it doesn't have to mean Optimus dies though....he may just quit.
I've been thinking the same thing. He gets lost in some time period and his solo movie explains how he comes back, sounds silly but it could happen!
