1) The Millennium Falcon will be destroyed in Episode 9.
2) Poe is not going to live long in Episode 8, but will pass on a critical plot line to another character.
3) Chewbacca goes home to his family on Kashyyyk, and goes through ritual re-birth after the loss of Han Solo.
4) Rey is related to no one, and there's going to be no effort to explain that point.
5) Episode 8/9 will explore the nature of the various force powers (electricity, mind-reading, telekinesis, intuition, etc)
6) The reason for Finn's defection will be explored in Episdoe 8/9.
7) General Organa will have a limited role in all future films.
The First Order will attempt to expand the empire beyond the galaxy in which they live.
9) "Good" versus "Bad" will not be a major plot line in Episode 8.
10) Episode 8 will introduce something fundamentally COMPLETELY new to the whole way Star Wars is though of.
Questions for speculative answers:
1) What's under the water on that ocean planet where Luke meets Rey?
2) Is there something special about the water itself?
3) Is the so called "Expanded Universe" (spin-off books, comics, etc) going to be tied in to the movies, or can the upcoming movie plots contradict the expanded universe events.
4) How much of Episode 8 will be non-linear in time (flashbacks, supernatural time warping, non-linear narrative, etc)?
5) Will anybody be anybody else's father/mother/sister/brother/cousin/nice's dog's brother-in-law in Episode 8?
6) Will any Gungan ever reappear in any episode?
7) Will any previously-known planet be visited in Episode 8?
Will Episode 8 have any "ghosts"/"spirits", like at the end of Return of the Jedi?
9) Which characters will continue to emerge and become more important, and which will play background roles?
10) Are there other elements of the "Force" that have not yet been expounded upon, which will become evident?
11) Are there other mysterious things in the Star Wars Universe other than The Force that can come in to play?
12) Will midichlorians be mentioned?
Feel free to provide speculative answers to any questions, or debate my speculative points, or add your own questions and speculation.