Quick question about level averaging

To a lesser extent, where these moments occur beyond their initial joining but to the main question:
Does Banon's level matter when new party members join your party afterwards in determining their level?

I thought I'd "easy route" a low level game by having Banon gain some solo XP a few times and get his level up (and score some nice GP too!) from a mockingly low Level 2 to roughly 10. I'm wondering if I left him at level 2 if Shadow, Cyan, Gau and Celes would join at a lower level?

Also, I think Shadow's joining level is +1 of average so could I potentially 'save levels' by neglecting to bring Shadow along with me???
I'm not against just testing for myself via ZSNES but I'm currently playing on the SNES Classic so it would take longer.