Go wild and ignore clearance or theme weeks. Or even if another contestant did the song already this year.
Hearing the song "Taking Chances" as background music in something today made me think of this. It's probably the only Celine Dion song I've liked in the past decade or so, and it occurred to me that it would be a great song for Allison, because unlike most Celine songs I can actually imagine it being done with a slightly lower register, like Allison has. There are some high notes in the song, but those can be played down since most of the song is a lot more mellow.