So who would be the new characters in a new far-fetched banner? I know Kliff but who else?
I think Owain is in that list, assuming they don't write him off as Odin. At least he a different unit type than Inigo/Laslow and Severa/Selena.
I actually went through and looked at the top 100 from CYL2, here are the units not in the game (that aren't FEH OCs) in order:
Selkie*, Owain, Kliff, Keaton*, Aversa**, Panne*, Kaden*, Velouria*, Tibarn*, Haar, Charlotte, Ranulf*, Louise, Severa, Rinea, Nils, Rinkah, Lethe*, Ranulf (RD)*, Lilith, Cormag
* Beast Units
** Likely an eventual GHB
So the likely ones for a Farfetched Banner are: Owain, Kliff, Haar, Charlotte, Louise, Severa, Rinea, Nils, Rinkah, Lilith, and Cormag, in that order.
If you discount Owain, Severa, Rinea, and Lilith, that leaves Kliff, Haar, Charlotte, Louise, Nils, Rinkah, and Cormag as the likely candidates.
Also people
really want beast units.