For your question on scores, forScore is the absolute best for this.You can export them once you mark on them, use multiple colors/brushes/tools, and it also has a handy ruler I like using for keeping highlights orderly too. You can make playlists for gigs, and it just generally works.

It's pricey, but it's worth the price!

Program wise, check out Canva, it's probably your best bet, teachers get free pro accounts.