My protagonist develops relationships early and gets kidnapped
In my literary fiction story spanning about a decade, new relationships develop, they join with the street gang. Old relationships fade. I need to preserve or augment the character’s impact while characters are off screen for long stretches, because they come back in to play toward the end.
The major conflict is a return to society as part of the gang.
Are periodic bumps (minor mentions) by flashback needed to nurture a reader’s affection, or can you abandon characters for several chapters and patch it up at the end?
Note: An example I know of is the character James Steerforth in David Copperfield, who is a role model and bonds with the protagonist in school. Steerforth goes off screen in Chapter 9, gets mentioned only twice in Ch. 10 & 12 in memories, and then vanishes until Ch. 19. He then becomes a major antagonist character and is hunted through all of Europe for eloping with Copperfield’s childhood friend who was already betrothed.
That was literary fiction 170 years ago, and it was published as a serial (essentially a soap opera). I would like to know if supporting characters in a modern literary fiction novel with modern audiences needs more maintenance.