I am working full-time this year with Williamson Music 1st as the Director of Curriculum & Content. We just released the 1st edition of RC Theory which is a music literacy (theory) platform that I've been working on for the last 8 years while teaching middle school band at Myers MS and Killian MS.
RC Theory covers all rhythms in 4/4, introduces cut-time and 6/8, teaches both treble and bass clef staff notation, piano keyboard, basic composition (with a goal of writing your own 4-measure melody at the end of the program), and vocabulary. There are 36 lessons and worksheets that are designed to be done on a weekly basis in the first year of band.
This might be helpful for you. Shoot me an email at email@example.com if you'd like to learn more!