I also think that he's talking about Jughead's interest in (crush on?) Betty. He mentions them filming episodes 2 and 3 at the time and Jugs' feelings had yet to be revealed at that point. Although when I rewatch those episodes, it's definitely there and there are some little moments and hints. I'm just so glad Betty asked Jughead to join the B&G because I have so been enjoying that storyline.
I do hope they mention something during episode 10 about it being Juggie's Sweet 16 just so that mystery is cleared up. And I'm just
at the fact they get him a hamburger-shaped birthday cake. I wonder if Reggie and the team will continue to bully Jughead now that he's part of the Scooby gang? Or if bad stuff continues to come out about FP and if FP possibly gets arrested, will that make him an outsider/target again?