Laura, interesting assessment. If we look at the story with David as the Protagonist, there are a lot of Trickster dynamics at play. Or perhaps better to think of them as you portray them: Characters evolving from one type of relationship with David to another. Ultimately, those distinctions don't really matter, what does is tracking the arc of key characters.
I do feel confident in this: Soonja is *definitely* a Trickster. Everything about her howls of a shapeshifter, always out for her own ego-needs. Her oncoming dementia plays into that. And the fire is completely a Trickster type of thing. But then her suprising comment to David about him being "strong." Tricksters can also act as allies and that is an example of such a moment.
Paul feels like a Mentor figure. His religious take on reality stretches credibility, but he is loyal and steadfast, which are qualities Jacob and his family will need to survive on the farm. Also, he has faith, another quality Jacob's family needs.
I might be inclined to look at Johnnie as a False Attractor. David aspires to be one of the gang and hanging with Johnnie provides that opportunity, however, Johnnie has a wild streak and that stands in opposition to the steadfastness required of the family to survive on the farm.
I'm not sure what to make of David's relationship with his mother and father. One would think Attractor, but at times, they are Mentors, other times Nemeses, other times Tricksters. Perhaps this is one of those situations where we think of them as Attractors - obviously David has an emotional connection to Jacob and Monica - and in those moments where the parents are arguing or angry with him or working angles with him to get him to see either of them as his favorite - as "mask" moments. That is, their Attractor function doesn't change overall, rather they don a mentor, nemesis, or trickster mask from time to time to fit where they are emotionally and support their goal at that time.
Simple plot. Complex characters. And an interesting exploration of two subcultures: Korean home life and the rural south. This is *exactly* the kind of movie I like. Look forward to watching it with my family on Easter Sunday.