Allison didn’t seem very happy with Somebody to Love, so, if they had a huge list to choose from, why would she choose a song she didn’t want to do????? She acted like Cry Baby was the lesser of two evils.
I would say when they get the list they pick 4-5 they want to do then they try them and listen to the versions out there and pick 2. Plus they discuss it amongst themselves and the coaches. But they have only a short time to pick plus the band can’t learn all the songs so they narrow it down to the one that they think is best and get the music and make any changes they want to the song then get it to the band for rehearsal. So by then it is down to two and one is the main the the other is the back up if the first one is not working out so well. They only have X-amount of rehearsal time with the band to learn the song so if they make a bad pick there is not much they can do at that point.