Music Supplement Deadline Questions

I actually have two questions. So out of the schools I applied to for RD, Tufts Brown and Brandeis have options for music supplement submissions. All of them direct me to SlideRoom to submit my application. Here are the problems:

I have indicated that I want to submit music stuff for Tufts, but I missed the deadline for Tufts music supplement submissions. I’ve submitted my common app and writing supplements before Jan 1st, and forgot about the portfolio part cuz I was too busy with submitting other apps. Is that going to hurt me? appsupport@commonapp.net emailed me about my success in submitting my common app, and then said something that’s freaking me out:

“You indicated you would include a Portfolio submission to Tufts University. Your application may not be complete if you have not yet submitted the Portfolio.”

Does that mean my application is unreviewable before I submit my portfolio? But I missed the deadline, so does that mean I’m screwed for this school?

Brown and Brandeis have deadlines in Slideroom for January 30th and March 1st respectively. I’m kinda chickening out of submitting a musical piece, can I just not submit one even though I indicated that I will? Would that hurt my results or kind of delay my application review because it’s not considered complete without the musical piece until I pass the deadline? And if I want to submit my music, should I do it ASAP?

I’d really appreciate it if someone can answer these questions, because I can’t find people in the same situation I’m in right now.