I think that's a very good read on the Betty/Jughead thing.
My gut feeling is that things between Betty and Jughead will change dramatically when she learns about whatever's happening between Archie and Veronica. Betty may feel betrayed by her new best friend -- what was left unsaid in the conversation about the scone was noticeably uncomfortable -- and she may decide she wants what she can't have -- Archie.
Note that Betty looked uncomfortable, and had nothing to say, when Jughead (in his tirade) suggested that she'd drop him in a minute if Archie changed his mind about her.
That seemed to hit a nerve--and she didn't deny it.