I’ve noticed something about Shimotsuna’s cognitive versions of her parents I think the creepy looking clowns and I might have a theory. they have some things in their chests that look like stuff from her childhood or when she was a baby like for instance inside her fathers chest (the tall clown) he has a baby pacifier and her mothers (the short clown) I can’t tell what it might be but it looks like maybe a baby toy flower.
This might be a bit of a stretch for my theory but what if these things are like memories of her parents and maybe that’s the treasure and when the thieves send the calling card they have to fight Shimotsuna’s cognitive parents to get the treasure(s).
Ah, yes, I noticed there was something in their bodies when I first watched the trailer, but I got distracted by translating everything! Here are the clearest views that I think I can get from the trailer:
I agree that her father definitely seems to have a pacifier in his chest, that one looks clear. Her mother is trickier, though. I'm not sure if you had a specific flower toy for babies in mind, but it seems like this is more than that...? In general, I think you're most likely correct that it's something baby-related, though.
As cognitions, these two would have to be based on Shimotsuna's memories of her parents in reality, but also warped by Shimotsuna's distorted desires. Unless they're shadows (not her parents' Shadows, but just general shadow enemies), they should reflect how Shimotsuna sees her parents, and may not necessarily be what they were really like. Think of other cognitions from the series, like Kamoshida's cognitive Ann, Shiho, and Mishima, or Okumura's cognitive Haru; it's just how the Palace ruler thinks of that person.
With that established, I don't think either of them have Shimotsuna's Treasure in their bodies. It doesn't seem like the infiltration route will even be secured in this update, for one, so I really don't expect to see the actual Treasure. And on top of that, the apparent connection to babies makes me think something else: it makes it seem like her cognitive parents really value (by some definition of "value") their child(ren).
There are a couple ways that could go- given how gaudy and unpleasant (thought fun!) her cognitive parents are, that doesn't seem to reflect entirely positively on them. I talked about their appearances in general here, though, so I'll focus on the baby (?) stuff in their bodies. We've seen they seem to dote on Shimotsuna, so it could mean that they see her as their baby, something to protect, and they closely guard parts of when she was literally a baby. The objects could also represent their memories of her as a baby. Maybe that means they never saw her as more than their baby, though?
Alternatively, her mother in particular seems round enough that she could possibly be intended to look pregnant. It could be that they were expecting another child, and Shimotsuna saw them as only doting on her for as long as she was their only (or youngest) child. If they're no longer alive, it could be that they died while expecting another child, instead, or something like that.
With the limited information we have, though, I could probably go on endlessly theorizing along those lines, haha. I think all we can say for sure is that some kind of baby (or perceived baby) is really relevant to how Shimotsuna sees her parents.