So generally speaking how acceptable is it in a 3rd person omniscient narrative to "flavor" the dialog in such a way that makes the narrator seem to have a personality (for example something like "Matt took a little baby bitch sip from the drink that was clearly way too strong for him.") despite the narrator not being a character in the story? I'm kicking around the idea of repurposing a screenplay I'm sitting on into literature, but comedy is a big aspect of it.
A little baby bitch sip...? Anyway it's common for an omniscient narrator to be a character in its own right, and I don't mean a physical character running in the story, but simply a narrating voice. It's usually a good thing when the narrator has its own voice. It sounds like perhaps you haven't read much from a 3rd person omniscient POV, so my advice would be to read books that do that and learn from them. It's a tough POV to write from because it's easy to confuse readers with the head-hopping and hard to keep your voice clear. ETA: doesn't Terry Prachett write from the omniscient POV? Read him, esp since you say comedy is a big aspect of the story.
Pratchett was my first thought too. Also thought of Lemony Snicket's A Series of Unfortunate Events (I've got YA on the brain today, judging by this and another thread). I'm not super well-read when it comes to comedy, but from my limited perspective narrators with character seem common-ish. It's certainly easy to see the comedic potential. But like with any character, you want to make sure the narrator is likable or at least enjoyable, and since they're always going to be there it's definitely the kind of thing that could make a book unreadable if the reader doesn't find them that amusing.
Jane Austen's another who does a good job of having her omniscient narrators slip in a bit of commentary/humour. (The opening lines of P&P are famous for a reason).
My 2p... I would say that consistency and purpose are your focus in this endeavor. It's not a common thing to read these days, so having it just pop up here or there in a modern work would feel more like a slip than a purposeful thing. If you are going to give the 3rd Person Omniscient narrator a personality, a mode of speaking, then do it, don't half do it, if that make sense.
