Though not much is being revealed about the story, it is confirmed that
A. Pyramid Head will NOT be back (his appearance in Homecoming was dumb)
B. The Order will NOT be back (They were wiped out during SH2/3/4 and brought down again when they resurged in Homecoming)
C. Murphy Pendleton (main character) is totally unrelated to The Order/History of Silent Hill
D. A postman named "Howard Blackwood" appeared in both the "Past Life" prequel comic and the trailer for the game - even though Past Life was set in the 1800's
E. Downpour's story is standalone like Silent Hill 2's