roundisfunny
Senior Member
In BTTF 2, Marty sees a billboard for the Cubs winning the series (in 2015) against an unnamed Miami team. Biff has nothing to do with it, nor does he mention any World Series in the movie.
As for the alternate 2015, it WAS changed around when Biff landed. In the deleted scenes (DVD), we are shown that elderly Biff disappears shortly after his return. Just like Marty in BTTF, Biff erases his own existence by his actions in the past. The neighborhood could just have easily have changed, as it was dark and deserted by the time Biff returned, and Doc and Marty were none the wiser. Marty and Einstein were just "poking around" the neighborhood anyway, and Doc was busy hustling Jennifer back to the DeLorean when old Biff returned.
As to why neither Doc, Marty nor Jennifer were affected upon old Biff's return:
In 2015, old Marty and Jennifer live in Hilldale, but in 2015-A, old Marty is the 47-year-old version of a "snot-nosed brat" who was in a Switzerland boarding school (one of many) at age 17. We're not told what happened to Jennifer, but it's a cinch that she didn't wind up with Marty. While the rift changed the future personae of them both, it didn't affect them at age 17.
Doc and family spend their years zipping through the space-time continuum, so they may have acquired some sort of "temporal exemption" for having leapt the boundaries of space-time so often.
Works for me.