My Dream -
The beginning feels a bit sudden. I like the simplistic idea you mentioned with the 3 notes branching out. The more dissonant/minor sections clash with the intended "fun" feeling I think. I would have started with a "happier" sounding trio of notes, as I think this track sounds a little more creepy than intended. Lovely soft section at 2:07. Very cute little piano run at the end, I love that.
My Nightmare -
I like the use of pauses/silence. Cool downward scales at 0:28. The low string line at 0:43 has a good feel to it. I do think it gets too major/happy-sounding for a moment there considering this is a track about nightmares. The section at about 1:20 is really interesting, I like the back and forth, and the dissonance.
Both of the tracks were fairly interesting and kept my attention. Plenty of potential here. Congrats on your submission and getting in some good practice! Keep at it. :)