The game doesn't follow the official canon much, anyway.(Go figure--semi-based on the mini)
According to the novelizations/adaptations of "Saga of a Space World" and "Living Legend", Cain and Adama were wingmates aboard the battlestar Cereberus under the command of Odysseus. Maximum Press fleshed this idea out in "Asylums 1 & 2". (I.e, neither started out aboard the Galactica!)
Tigh was either 1. a replacement for Cain when he was transferred to become the new strike commander for Pegasus("Lost Planet of the Gods" novel) or 2. an Academy classmate of Adama's who arrived on the Cereberus weeks(sectons) before Adama(Maximum Press).
(And yes, he was still Black!)
But then they probably couldn't figure which Tigh (old/new) to stick in there given the fan uproar.