I’m not sure how the “transferable unit” system works, so I can’t speak to that question. In answer to your second question, I had a similar problem a few weeks ago - I forgot to report any of my AP scores, so it looked like I had failed the tests and didn’t want the results to be shown. I spoke with my school’s college counselor, who had the e-mail addresses of some of the admissions representatives at my target schools. He said that if I e-mailed them within the next few weeks explaining the situation, it would not be a problem, and they would add the new information to my application.
Hope this helps! You should probably speak with your counselor tomorrow morning.