I think that adding 3 new colors will suffice:
Card N'FoRcE wrote:HardRock and Doubletime could share the same colour since they're meant to make the map harder (while FL and hidden only "hide" things) and if one of the hiding mods is used with HR or DT we can have another colour to explain that
1 for DT, HR or DT+HR (red maybe).
1 for DT+FL, DT+HD, HR+FL, HR+HD, DT+HR+FL and so on... (all combinations between DT,HR and FL,HD).
1 for DT+HR+FL+HD (all mods).