Hi Zaira! I'm in the same boat, although I have a short story (5 pages, flash fiction) and a novel excerpt (19 pages). That leaves me with 24 pages, and that's not enough for the 30-page minimum for IWW. I think that's just a recommended page count though, no? So if you submit 20-21 pages to IWW, you wouldn't necessarily be out of luck. But I do think that since you have three pieces to submit, you should submit all three--especially if they showcase your range and are already workshopped and polished (major kudos to you for that!). I'm no expert, though, so take my advice with a grain of salt.
I totally get overthinking this, haha. I'm doing the same thing. I'm only applying to two programs this year, since I can only afford two and it's my first time. That's probably outrageous by some standards, but oh well, if I don't get in this time, I won't sweat it. IWW and/or JHU or bust! Hahaha.
I'm interested in asking you about the content and style of your writing sample, actually, if you wouldn't mind sharing. How do you know if your pieces are thematically and stylistically relevant and/or captivating for an admissions committee? Do you have any insights to share from your experience workshopping pieces over the summer at IWW? (Sorry if I'm mixing you up with someone else!) My novel excerpt, more than my short story, shows off my grasp of dialogue, humor, scene-building, etc., so I'm inclined to keep it as a part of my application package. My short story is more experimental and disjointed, if only because the subject matter requires that sort of formal experimentation. That sounds pretentious, sorry lol.
I watched the IWW fiction application advice YouTube video, and one of the writers said that they focus on "pain point," or whether or not the piece understands how to write productively and beautifully from a place of pain. They said that bells and whistles aren't necessary (thank goodness), and that it's more important to have a piece with urgency. It must demonstrate that only you can write this story with urgency and truth. Beautiful passages help, but I think authenticity helps more. I hope I've demonstrated that in my writing, or at least hinted at my potential in some way.
I'd love to hear your advice and ideas, and I really appreciate you reading this! Thanks so much. Best of luck to you!