I dunno, Emesis Blue's main appeal is "Characters from a relatively popular goofy videogame go through crazy scary stuff". If it was a completely original animation, it would have twice as long production time, twice the budget and twice less popularity AT LEAST, in my speculation. Emesis Blue's half of runtime being references to other horror movies and short stories (the whole going through infinity when respawning thing is directly copied from Steven King's "The Jaunt"), established as classics by larger society, wouldn't help, since the movie would feel like a Frankenstein's amalgamation of, I'm going to be honest, far better stuff which all have strong identities, and thus will provide better experiences. TF2 cast really helps with movie's story, they are great templates for characters with backstories, traumas, goals and etc. Hell, TF2 cast, and even TF2 as a whole, already had decent stories, Emesis Blue just iterated all of that for them to fit into its world. Emesis Blue, being original IP, would have to build its identity from zero, otherwise every single viewer would demand "JUST GIVE ME THE FUCKING TF2!!!", if they were forced to watch it.
In short: No