Estella will become the Champion of Carst after coming to terms with her trauma and putting aside her regrets or thoughts of revenge. She'll mature a great deal and become a far more graceful and grateful woman.

Gareth Falcry will wind up bonding with the legendary he is seeking and ultimately turn down the offer to become Carst's Champion, instead focusing on his duties as lorekeeper and spreading more information about Carst's legendaries so that they can all co-exist peacefully.

Agent Albion will ultimately leave Zygarde's side, realizing he's not fit to work alongside the legend, and settle into a smaller law enforcement role - trying to help out communities on a smaller scale rather than forcing himself to carry the burden of an entire planet on his shoulders.

Lorenz will ultimately grant Lucrezia the peace of mind needed for the poor Zoroark to finally pass on. The details are a little murky still lmao