1: Seam (field shopkeeper) and Jevil worked together
2: Spamton is a shopkeeper
3: Ramb(green room shopkeeper) is involved with the sword route
4: Gerson is a shopkeeper
5: Pink is a shopkeeper
This probably doesn't mean anything just thought it's interesting, very, very intresting 
Seam boss for PureCrystal in Chapter 6 confirmed?!?!?!?!?! 
Yeah this is the secret boss for chapter 6
I know because I am the image_fraud- I mean friend
Swatch secret boss confirmed!? <☉o☉>
/J
Mike fits here too because they were the one who is close to Spamton.
Oh him, he was forgotten to be honest. Unless we get another technology based world or a world with a phone we're probably not gonna see him
Mike is the FRIENDs we made along the way 
shops are an easy way to build up small relevance while also leading into an easy gateway to an SCB quest; like selling you an item that gets you into the boss room
it's probably not lore or anything
just convenience
Some kings of Convenience Shop
perinmayhapschancedeed