Someone

Flowery - Idealized version of how close him and Rudy where. Down to even calling himself Asgore's "college roommate". Spends the whole chapter distracting Asgore from dire matters, possibly like how Rudy tends to brush off how bad his illness is. He does end up dying at the end soooo👀👀 (also can't not bring up the Chara/Asriel visual his death scene gives off)

Aqua - very obvious resemblence to a smaller Kris, Kris known prankster and mischievous in the past, even likes knives! While not specific to Aqua, the Flowers wanting to be human is a pretty sure mirror of Kris wanting to be a monster formerly. Her own childlike confusion of this also probably mirrors how Kris dealt with their own differences in Hometown.

Seth - tries to be really smart and plays a responsible older sibling role to Aqua but to no avail, most likely what Asriel's really like. Although their gender identity obviously fits more with Kris, it could be possible Asriel has his own hangups regarding his identity, possibly also following in line with the Trans Ralsei theory? But that's a bit of a stretch

Yellow - Asgore's own twisted view of himself, a sheriff who tries to be good at his job and has an obsession with dishing out justice is pretty much Asgore's entire main involvement in Deltarune. We know his favorite show is cowboy themed, he could very well see himself in that show's protagonist Also I do not doubt that man being suicidal.

Blue - his relationship with Yellow possibly mirrors the comfort Asgore seeks in being with Toriel, Yellow literally shows his love to Blue by gifting him a bouquet just like Asgore always does. Although my brain can't really make any ballerina connection to Toriel at the moment, could just be how beautiful Asgore sees his wife but idk.