In regards to Jon. I do want to keep visiting him throughout the story just not as much as the others that are currently changing. Also as for Karyn I guess she has an easier time believing because she knows the rock exists and therefore thinks that she can somehow help.
As for Linda and Roger. Roger is showing a little concern for Linda but he thinks that she is just not feeling very well as she hasn't had as quite an outburst about the situation as Jon has (if that makes sense).
Perhaps if Roger trades his sensitivity with Linda then Linda might get Roger's anger (or something) and then the next time something swaps then Linda might have an outburst.
I had planned for a chapter that when Karyn gets home she is upset about Tim asking Jon out (because she obviously loves Jon) and then she would be comforted by Roger who is now more sensitive and can give her advice on how to win Jon back I.e do something romantic.
As for the clothes bit, there have been times at the start when the characters thought about getting new clothes (when Jon first switched underwear) but they always had something to do that distracted them. So maybe every time they plan on going to get new clothes they always conveniently get distracted and then forget
I hope that helps
