This isn't a port, it's an update (although you can be sure that the console version will receive this mode for sure)
Also the 1 vs 1 option was in the console port of the original Tag, it's the 1 vs 2 that's unique, especially cause it doesn't seem like the Rage system works like it does in 2 vs 2 or 1 vs 1. In 2 vs 2 it requires tagging while your partner is enraged (due to you getting hit alot or with certain moves), in 1 vs 1 it's like Tekken 6 where it occurs when you are at a sliver of your health, but in 1 vs 2 it seems to activate MUCH earlier.
And yes the relationship between your characters can enhanced (or hinder) your rage conditions when fighting as a team (another thing to consider when forming your team, but it's not a total deal breaker if your team isn't "optimal".