I downloaded the demo and I like that you’ve re-thinked it from the scratch. Seems very very promising even though it’s unusable for me at the current state. I’ve been mainly using Sibelius and tried other softwares like Finale and Guitar Pro and although they have their strong points, I ended up getting frustrated with them. Especially when it comes to the banjo tablature.
I know this might not be your priority any time soon, but when you get to the tablature for fretted instruments, please make sure to get this right! The 5th string of the banjo doesn’t have frets 1-5, because it starts from the middle of the neck. Furthermore, if you built the whole tab engine so, that it included an option for customizing the starting fret for every string, that would make it easier to tab for a banjo that has a capoed 5th string which is used a lot. Also it would make it possible for guitar players to make tab for partial capos and such without having to make a ton of different instruments for different tunings.
Feel free to contact me, if you need a banjo/guitar players opinion or beta test when you’re developing the tablature feature!