The workaround we found to work best is that everyone had to agree upon a common set of task categories, and then make sure to individually change their class settings to match the categories and colors. This isn't too hard, and doesn't take too long, but it is a bit on the back end of things, and ManageBac is notorious for having hidden menus that you just have to know how to find. The hardest part is probably getting a group of teachers to agree upon a common set of task categories! Our final consensus was that we wanted students to be able to decipher between in-class tasks and homework tasks, and that they should know if they were formative or summative, thus:
Class Work - Formative Task (CW-FT)
Class Work - Summative Task (CW-ST)
Home Work - Formative Task (HW-FT)
Home Work - Summative Task (HW-ST)
We chose to make Home Work tasks green so they would pop out on the calendar (but not be red), and the classwork to be gray/black to be visible, but not eye catching. Summative tasks were the darker variant of the two schemes. Gray was a bit boring, and not everyone loves it. However, having all classes use the same categories makes the calendar so much clearer. We also go one step further by naming tasks using the HW-FT nomenclature too, i.e. Science would name a task Sci HW-FT Cell Worksheet so all vital information is visible the calendar.