Champagne is a white cougar Amigo that only comes with the paid Vice Pack. If you own the pack, she joins the Amigo roster without any mission to unlock her.
Buy the Vice Pack add-on and Champagne appears with your other Amigos. There is no Yaran Story or quest tied to her.
Like the other animal Amigos, you can send her to attack FND soldiers. The sources do not list her perks, so check the Amigo menu in game for her abilities.
Alfredo Máximo
Alfredo Máximo, called The Bouncer, is a La Moral soldier with a smooth tongue who ends up as one of your Los Bandidos operatives. He is one of the leaders you can send on Bandido Operations.
Image: UbisoftBoomer
Boomer is the dog from Far Cry 5, back in Far Cry 6 as a stealth Amigo that Dani calls Boom-Boom. He tags enemies around you and pulls loot off bodies, which makes him the best pick for scouting a base before you go in.
Image: UbisoftChicharrón
Chicharrón is a punk rooster Amigo raised for cockfights who would much rather peck FND soldiers. You earn him in El Este by helping with his grudges against the regime.
Image: UbisoftChorizo
Chorizo is Philly Bárzaga's dachshund pup in a custom wheelchair, and one of the best stealth Amigos in the game. He distracts guards so you can walk up and take them out quietly.