Some sort of white from House Stark, from Game of Thrones maybe. Or grey, because stark normally invokes a bleak color.
I know Oberon and Savas have met before, and you mentioned Ribeiro knowing Savas. Kei hails from Mistral, and Acero Atlas, so this would make the other pair interesting to act out.
For the initiation itself, I personally feel that a FFA wouldn't exactly work if we were trying to introduce ourselves to each other, since all we would be doing is combat. Perhaps, being 4th years, we could be assigned a mission (Search-and-Destroy/Rescue or something of the sort) right off the bat, instead of having to go through initiation tests. However, that "mission" would act as our unorthodox initiation.
If our other members disagree with me, though, I am perfectly fine with going along. It saves us the time of needing a DM, apart from the beginning, because simple fighting between each other does not require such a member.