Here’s a breakdown of the characters in Crazy Rich Asians per their character archetype functions:
Mentor: Peik Lin, Oliver
Nick’s siblings and their spouses each have their mini-arcs and to the degree they interface with Rachel play like Trickster characters in that they create complications and in some cases work against Rachel’s goal of fitting in with Nick’s family.
Astrid, however, feels different. The whole tone of the Astrid — Michael subplot is more dramatic than almost every other relationship in the script. I’d be curious to talk with the screenwriters about their take on this subplot. My sense is Astrid exists in the story as a kind of morality tale… “be careful what you wish for.” Yes, Rachel may marry into money and money may seem a wonderful thing, however, it cannot buy happiness, it cannot substitute for love. And it’s intriguing that there is a point of connection later on in the story between Rachel and Astrid. I haven’t read the sequel to the novel, but my hunch is their relationship gets explored more to depth in the subsequent story.