Hello, I was able to listen to the first song and really understand your frustration because it has happened to me in a similar way.
The quality of the sounds are very good and I like your composition and can tell you are musically talented. I am pretty sure this rejection is not related to the quality of the sounds or mix, although bass is boomy in some sections probably due to the low notes on the cello/double bass when combined with the piano low notes. I am 99.9% certain that the rejection is due to the mood/style chosen which is quite different from the AJ market place. The chord progression of the main theme is somewhere close to: vi - I/V - II/bV - IV (in major mode), which sounds quite complex or more sophisticated due to the third chord (C/E, [II/bV ]) and not close to the typical AJ progressions In a similar fashion, the change in key at 2:52 from minor to major although very well thought out and nicely expressed, is something that got one of my submitted tracks hard rejected a while ago; it’s not well received among the AJ reviewers. My recommendation with all the effort you have put into that composition is to have it released along with other similar songs in an album. But for that I recommend you to mix the piano a little less hot and do some EQ tweaks; then have it mastered by someone else, among other things. 
Wish you success in the near future.