Personally i have a strong squad 1 (cause thats the helper team) and i spread power, speed and aoe/single skills evenly between teams 2, 3 and 4, and thats the setup i usually use to complete maps, except if they need a certain speed, and about colors being mandatory, i dont think so, if you dont have any strong blue for example, dont put any blue in your helper, i had no strike girl in my helper team for quite a while until i got cactace, heres my team atm