1st off
Griffith won't be too much of a dick, he will start off as a full-of-himself asshole, but over time will eventually become a nicer guy
Inigo will undergo a similar development, but he's more comic relief if anything.
Siegbert will remain an asshole in the story and will never understand why he lose to Jalen
The 3 males are Jalen's 3 rivals btw
Lucina and Severa will leave Team Plasma midway in the story and will join Jay and Rin on their journies
Griffith and Jalen will have a dynamic relationship
Rhiannon will also interest Lucina and Severa in a way
As for teams...
Jalen will have the starter(Litten) that's strong against Inigo's(Snivy) and weak to Griffith's(Piplup) and is neutral to Siegbert's(Charmander)
Lucina will have a primary Water team to Severa's Fire team