Accidentally watched all of season 3 since yesterday . The ending was solid and I am really starting to enjoy the pace of the seasons. You get plenty of action over the course of 1 episode plus it sometimes only advances the story a couple hours.
I really dont know what they'll do with that. It would be too predictable to have her join them. It was also SLIGHTLY repeating the first heist with how Raquel found him as well.
Also, here is another theory of mine (though I doubt its not original). We eventually find out everyone but Tokyo is dead. I've been noticing she is the only one that narrates the show. It makes me wonder if shes retelling the tale to someone.