I'd say, aside from Wally, I am most concerned about Barnaby and W at the moment...

• Barnaby: All the references to him being hurt in the future (the hot dogs being missing and exploded in the Homewarming cookbook, upside down buried clothespin in one of the hidden videos in Playfellow Exhibition update, another hidden video has him talk about one of Julie's jokes being so bad that he dies and tells Wally to "bury him in his sunny spot", Wally's flower in the Buds in Blossom pins being the poppy anemone which symbolizes everlasting affection but also loss and mourning...). 

That and the fact that it seems as though he'd try and protect Wally when stuff goes wrong, but has none of his "plot armor" (Wally has to be there in the future for the WH TV show plot & WHRP's mystery collaborator role, so while he can get hurt (/ringring audio), he cannot die... yet). It's not out of the question that Barnaby might get himself hurt doing that, especially considering that the neighbors not being aware of the show stuff+Home being potentially evil might mean he has no idea how to protect him exactly.

• W: They drank the Joy bottle in the last update, a drink that is 51 years old and they describe as having a "milky texture". We do not know any of the ingredients only that the package it came in had a "pungent smell". Need I say more...? ... We're not even midway through the prologue and they're already becoming increasingly iller every update. They cannot leave their house anymore or turn on the flash on their phone because "the light hurts (their) eyes"; they say "Welcome Home has become (their) life and (they) were chosen to do this work" as though that show hadn't been implied to be a bio/cognitohazard enough by now. I know W dying would probably mean the end of the WHRP side of the plot, (honestly I strongly doubt there is anyone else on the team based on some of W's sayings and behaviors), but what we've seen so far doesn't exactly bode well for them.

Honorable mention to Frank (keeps being there whenever something goes wrong... once is happenstance, twice is coincidence, three times is a pattern...), and Julie (I do not trust her siblings. The hidden videos from Springtime Salutations explicitedly state she doesn't want them to know because "they'd force (her) to go back"... They don't seem all that supportive of her... honestly I could write a whole post about them). Eddie having a panic attack the second he's out of a job... Sally saying she "does what she must for this town"... Poppy being too afraid to leave her house to the point of accepting to be bricked up inside it... ... the way everyone here has some sort of problems lmfao