My bet is that it will be a story in which the teen-agers get upset at the parents trying to control their lives, they come-up with a scheme to "get back" at the parents by showing they are "adults" and not just little kids (with plenty of inside jokes referring the fact that the series is 75 years old).

They "stage" a proposal in order to show the parents that they are older than their parents give them credit for.

Then... option #2

Archie/Betty or Archie/Veronica are cleaning-up an attic and looking back at all the old times they and their parents had (tying back to the series history, of course).  They find an old trunk with wedding photos and even the ring of Archie's great or grandparents.  Archie then fake "proposes" to (and, I'm thinking Betty here).  The gang gets wind of this and freaks out - especially Veronica. There are all sorts of back-and-forth comedic and serious moments - again reliving the series history.

In the end, they realize they are too young for the responsibilities of marriage and it's all resolved with Archie, Betty and Veronica sharing a soda at Pop Tates (and the original art being sent to some lucky, obsessed fan that guessed right!!!!)
 
(I can dream can't I?)

Archie marries Jughead. He's driven wild by the majesty of Jughead's long, giant nose.

Jughead and Wendy?

That's about as believable as Jughead marrying Mrs. Butterworth! 

Maybe it's just a red herring. Maybe it's Polly or Chick who is getting married, but somehow there's a mixed up and Archie is in the middle of it.

Good call - that's likely.  It may be that Archie is the best man or a groomsman.
Maybe it'll be Reggie getting married and they will have the character leave the gang!  I hope not!

Archie obviously can't get married unless it was a fantasy sequence, or a story that takes place in the future.  And Archie can't walk down the aisle with either Betty or Veronica, because that would be seen as him finally choosing one or the other.

Wait until you see the cover. Next week. Archie will choose.

Maybe a mad scientist created a teenage girl with two heads -- Betty's and Veronica's!  Archie can marry them both at once!

Katy! Cricket! Wendy! Evelyn!