Online seems to be up! Testing out the options now.
It seems 2 v 2 is in, at least I think so.
I set up an online friendly match room and there's an "add guest" option which then asked me to press start on the second controller. Did this, selected personal data for player 2 and now it says "Me + guest" as the home team.
Edit: More info. When you select ranked match, you have some filtering options:
Matchmaking level - any, +/-50, +/-100, +-200 (the number is the difference between your level and theirs)
Team class - any, Class A, Class B, Class C, Class D, Class E - this splits the teams into classes, Class A is Spain, Argentina, Italy, Barca, Real, Juve, United, PSG and City. Class B is Liverpool etc, and so on.
Support setting level - no restrictions or 'similar level - you will not be paired with opponents who play with control support settings that greatly differ to yours' (assume this is manual passing etc)
Add guest user - "If set to on you will only be paired with others who also have a guest user" - sounds like ranked 2v2 to me!