Notation Software

This is a free downloadable notation software that is fully functioned. Professional musicians use this.

https://musescore.org/

Free Online Homeschool

The landing page for this doesn't really give me enough information to recommend it or not. It doesn't appear to be customizable. But it says accounts are free and it claims to be a full PreK-12 school online.

http://discoveryk12.com/dk12/curriculum/

If anyone has used this, please put a review in the comments.