I've always been curious about the British Invasion. Curious about how they were going to be released. My original theory was that, just like the 5 15 CP heroes, a player would be given one for free and the rest for purchase. But, my prediction was shattered once Psylocke became a PVP Reward. So, I modified my prediction. Here it is!
Hmm... Psylocke=PVP Reward. So, one of the 3 might be a Spec Op reward, while the player has a choice of choosing one of the other remaining 2 for free and the other for purchase. Confused? Here's an example.
Union Jack is a Spec Op Reward, and the Player can choose between Black Knight and Captain Britain. Just like the five 15 CP heroes, one is free, the others cost CP. So, the player might choose Captain Britain and Black Knight will be the character for purchase.
Basically, one is a PVP Reward (Psylocke), one might be a Spec Op Reward, one for free, and the other for purchase. The characters will be released, but maybe not in this manner.