I really think Kris was closer to Dess than they were to Noelle or even Asriel, and that Dess was the one they were playing pretend with in the past(since Noelle doesn't recognize anyone from Cyber City).
It just makes a lot of sense since Asriel and Noelle are the "golden child" of their respective families while Kris and Dess are the weirdo outcasts.
I don't get why people immediately assume Kris was that close to Noelle when some of the dialogue implies they became friends by proximity, because Kris and Asriel befriended Dess first. Maybe Kris even disliked Noelle initially hence why they used to harass her but was fine with Dess tardwrangling them.
By the way Kress sucks and fundamentally misunderstands both characters.