It's a cool song and she is very talented....The music business today is a sad clustered up AI mess ...Unsure how it is all going to pan out but the game has surely changed. Hoping talent like your daughters still have opportunities to make a living at it if they want to. For sure the odds have gotten a lot worse than when I was a young man. Back then the odds were like winning the lottery. Today Oy!
I am about 3 weeks into Logic Pro and I love it / Hate it but it is super powerful. The online stem splitters do a more refined job e.g. separate the harmonies from the main vocal line but in literally maybe 20 seconds your track was split into vocal (that also included the harmonies) , bass, guitar, piano and drums. I just added a audio track dragged the vocal into it and inserted the Eilish vocal FX chain...boom done
I dinked around with the piano part this morning but I am still fighting the routing set up stuff to get everything running smoothly...for some reason my piano audio was way low....Ugh technology!
I also tried to use the session drummer but haven't figured out how to sync with the tune though I believe it is possible.
So far learning a lot but there is a ton to learn and playing with your track is good exercise in the learning process of using Logic.
All the best!