(p.s.Do gf's level up quicker when with sefier or something?explain)
It's not that its just that with Zell and Squall KO'd you dont need to worry about them gaining exp and therefore other monsters leveling up aswell.

So what it means is that when you are done with the dollet mission you will have a level <10 Squall but level 100 GFs to fight level <10 monsters.
See where that is going?