Begin captain in FIFA 17 in player career mode

So I have finally worked out how to do it...

You don't need the player to have the "Flair" attribute but it does seem that you need somebody with a decent "skill moves" rating. I this case I did it with 4 stars skills rating.

The team I used was USA, and I played a 4-4-2 formation with Rapinoe and Heath up front. Who have 4-star skill and 5-star skill respectively.

I achieved the trophy with Rapinoe (4-star skills, no flair trait). However, the button combination I used was in fact L2 + R1 + O. I don't know if this is required, perhaps it just a variation modifier for flair moves... but it does do the job.

Took a few attempts but basically you don't need to receive from a pass, you can just run at the goal and press the button combo, and some times it will just do a flair shot instead of a normal shot. Net it and the trophy will pop.

No there is not. Although I agree this would be a cool feature. The only way you could do it is play one season on tournament mode instead of career mode, then it should show Klopp as the manager.