Let us start at the beginning of the episode.  Buffy wakes up to a clock that goes loudly off at seven o'clock in the morning.  It is very significant in pointing from the start that the episode is really about what will happen in season seven.   A supporting reason for this idea is that we have a previous foreshadowing episode that occurred in S3 that used a very similar setting.  It was a dream that used a clock as a giveaway for a date, in that occasion it was 720, the days until Buffy's death in season five and also gave some foreshadowing of Dawn's coming.

But the whole episode is bursting in very specific foreshadowing.   While very characteristic scenes develop without sound we see Giles bringing to Buffy an axe that looks a lot like the scythe that is the key to an important plot line in Season 7.   Buffy leaves her doodling and follows him, I see this as a possible symbol of her having to take over the scythe and leave behind her relatively carefree days.

Another moment of similarity with an episode of season seven is for instance, the final of the only Spike's solo, the "Rest in Peace" number, where Spike and Buffy fall into a grave pit, and while they look into each other's eyes, Spike asks her to let him rest in peace.  She gets out of the pit and runs while he stares. This moment is pretty similar to what would happen in "Chosen", when Buffy has to leave Spike in the Hellmouth.

Regarding Spike, there is another moment that really pops out over the rest in the story.  Spike brings back to “The Magic Box” one of Sweet's minions, a wooden monster that flees after delivering a very specific message, Spike says then:  "Strong. Someday he'll be a real boy."   This moment has been regarded as significant, given Spike's obsession with Timmy the doll, which in my opinion symbolise his desire to become a man.  Here I am torn between the possibilities.  Is this meaning that Spike will have a soul in S7?  Or even farther away, that he will become Shanshued in a distant future?  Only time will tell if the second option is the answer.

Talking of this moment in OMWF, I see in the way that Giles and the rest of the Scubbies let Buffy go alone to face the monsters and in how Spike argues because of their abandonment of Buffy as a clear foreshadowing of the episode "Empty Places” where  Buffy is expulsed from her own home and sent away to fight by herself, while only Spike comes to her defence against her own friends, who give her their backs.    In both scenes, she ends up leaving alone.

Especially interesting is that from this scene on, Buffy and Spike are using the same clothes.  Something that I hadn't seen in another episode before.   Both wear black pants, red shirt and a black leather duster.  In my opinion, although not entirely foreshadowing, this is the clearest moment we have of their archetypical characterizations of shadow images and equals.   Totally beautiful.

The song "Walk through the fire" also brings a very clear foreshadowing of the episode "Chosen".  The fire is constantly brought up by Buffy, she holds up her hand and says she wants to be burnt, and in the future, she will have her hand not being peeled, as in this song, while she holds a Spike's burning hand.   Spike himself speaks of a torch that is consuming him, just like we will see in "Chosen".    Even clearer is the verse Buffy sings: "These endless days are finally ending in a blaze" as referring to the final episode.

The end of the song and the act has the demon Sweet saying just one word:  "Show time."   Which is the name of the S7 episode 11.

The song "Life's a show" also has interesting foreshadowing that reinforces the previous leads.  Spike stops Buffy from burning herself to death, and says: "You have to go on living. So one of us is living."   Again foreshadowing his sacrifice for her and giving her advice to continue her life. 

In the next minutes of the episode we find out that Xander was the one to blame for the Sweet situation and his reason was to have a "happy ending."    Sweet replies mockingly about that notion and repeats himself about this hardly being a happy ending:    "All those secrets you've been concealing. Say you're happy now, Once more with feeling.  Gotta run now, see you in hell. "     My personal interpretation of this is that Joss Whedon is giving away that what he considered as a happy ending for the series is really not so much so.  And indeed the story closes with many losses and one truth revealed.   Buffy loves Spike.   She learns it in hell, in the Hellmouth.

Now the final scene from Chosen is taken from the song:  "Where do we go from here?"    This line is sang by Dawn first and then repeated in very similar words by herself as the final line in the series: "What are we gonna do now?"

The rest of OMWF is still as telling.  Does it have the key to what is to come in Buffy's future?   I don't see why not.  The final act of the episode worked out in a great part as foreshadowing, almost word by word.  So let us get into it and have some face value foreshadowing interpretation.

While they keep on singing, Spike breaks from the group and goes out alone, as in his dying in the end of the series.    Buffy follows him outside, he tries to send her back to her friends but she resists.  He thinks she doesn’t know what she wants. And finally he says:  "I died"   and Buffy replies:  "I look into it and it's black.  This isn't real."

Which indeed if taken at face value, is true, because Spike returned to life in Angel the Series.   Aparently a great meeting of the lovers is meant to be, maybe Buffy trying to convince Spike of her feelings while he refuses still to believe her?   The final words:  "You make me feel." And the line sang “Where do we go from here?” and then finally the big kiss may foreshadow some real happy ending in a remote far away future.  Let us hope.