Would it be okay to wear a plaid shirtdress? It looks very professional but i don’t want a pattern to be distracting…
My D said that if she were going to do it again, she would have dressed more like a nicer version of herself rather than in a way she thought the auditors wanted to see. Mainly, let more of her OWN personality come through in her outfit choice than fitting in to the “fit and flare dress” that so many girls go with. They do look nice, but they look the same. My Ds most successful auditions were in programs where she wore pants and a button up shirt, not a dress.
Personally, I think the “jewel toned fit and flare with nude pumps” can end up looking a bit stepford. It seems most common in the MT auditions - but we saw plenty in straight theater too. My D did it for her 1st audition, took a look around the room, and never did it again. You certainly want to look nice, and I would avoid a “distracting” outfit (too much pattern, skimpy etc) but be YOU. After all, you want to stand out at an audition, not blend in 
For acting auditions I think it is important that you are wearing an outfit that reflects who you are and that you can comfortably move & crawl around the floor in. Schools come up with some zany twists, “Now do your monologue as if Juliet were a Basset Hound.” You don’t want to be worried that you are exposing them to more than your talent and personality. Also keep in mind that some schools videotape your audition so you might want to test how your outfit looks on onscreen.
My daughter took a a few fit n flares to chicago, freaked out, and ended up wearing nice dark colored skinny jeans, a simple top and her boots. She felt comfortable, looked really cute and like herself!