Red is the colour used for Unicorns and unicorn mixes. the fancy head gear collects leaked magic and store it for later use mostly in many of the Machines used in war times is also helps weaker unicorn case normally higher level spells. however if wear too long it can cause magic poisoning. So Unicorn with high magic levels like Gear (who I put in the hat because I thought it looked funny) can only use them sparingly.
Red/white: Bumble and Gear are wearing medial coat colours of red/white this coat looks the same one any of the races. they’re under jacket well the same colour as the other unicorn also tells use that they are in support roles do to the yellow circle and strip on their fore legs.
Green is the colour of earth ponies and Earth mixes, this ones also wearing hailing gear and studded hind shoes to increase grip.
Blue is Pegasus and their Mixes, this one is acting as a scout with a radio attacked to him. this radios are still pretty primitive mostly being useful for morse code.