Not sure if anyone already made a post about this, but now that we have FF Type-0 units as friend units, this is an excellent time to beat the new 2-headed dragon trial.

Summon an esper every two turns, and you should have an easy time beating him. Just made this few hours ago, and I wasn't vert prepared to beat it really...

Hints I can give to make the fight easier:

1. Bring a friend Kurasame or Machina that is a 7*
2. If you have any of the units above Rem, Ace or Queen as 7*, bring them too! (Rem is superb for this)
3. Every two turns, sacrifice one of these units with "Summon Eidolon" to fill your esper gauge, and hit the dragon with an elemental esper. Then, raise/re-raise the unit that died. I didn't bring Phoenix, but this makes the raise part much easier since the esper will bring the sacrificed unit back to life easily
4. On the other turn, hit the "dwagon" with your chainers/dps of preference
5. Bring an Magical AoE tank with Dark/Light/Thunder/Ice resist. You can cover on the turn that you use the esper, and defend on the other turn to reduce the damage even further
6. A physical provoke tank is recommended
7. Break resist can make this even easier. I ended up beating this without break resist though. EV will do great, specially if you can make him 100% evade, as he can cover the break resist part

In case you don't have any 7* Type-0 unit, you can play around with Entrust Garnet. Tidus is an excellent choice here, since he can chain with Kurasame and entrust Garnet on the other turn.

There's the cheese strategy as well, using an unit with Phoenix and hide - a quick search on this subreddit will show you a couple threads on that

Hope this can help people that haven't completed this yet