One thing that might be worth considering for 1. is to use the very useful graphic slices feature in Dorico to export the notation bits as graphics and use a more bespoke software like InDesign, Affinity Publisher (or even Word) or so for creating the text material and laying everything out. Might be easier than trying to make Dorico do the heavy lifting there.
This video is from a few years ago, so more features and capabilities have been added since then, but it shows some good fundamental principles of how Dorico’s flexibility lets you create music worksheets really easily and beautifully:
this is a great idea. I am familiar with indesign and Affinity Publisher. The reason I want to do all in Dorico is: I teach with an OBS Stream and just want to go through the screen and start the playback at some point, which would not be possible in Affinity.