We just finished Newsies and (like you) are Windows-only. We found London Arrangements had a complete score for it and it worked REALLY well.
They also have a Wizard of Oz (complete show) (londonarrangements.com)
When we did Matilda, we were so early in the process that they didn't have any backing tracks, and no promise of one in time either.
I found Sing Broadway Now – SingBroadwayNow which had backing for all the songs, and I ended up entering all the notes for all the incidental and instrumental music into MuseScore and generating tracks from , which also worked surprisingly well.
For our Wizard of Oz show (2019) we used Rick Frendt's projection suite. (https://www.rickfrendt.net/wizard-of-oz-projections)
We supplemented it with a couple of projections from Mitch Stark. (https://theatreave.com)
I second the comment that Mitch Stark is wonderful to work with.
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