Ultros should give us all tips.
It's an annoying trophy and it's quite repetitive but it should work out in 2 hours or so.
Try to get as much points with Chalcedony and Kunzite, should get at least more than 3.1k for them. Try this setup:
Kunzite:
Fleeting Shadow - Circle button
Tempest Strike - Right analog stick
Chalcedony:
Aerial Exorcism - Circle button
Soaring Radiance - Right analog stick
Be sure to attack the star balloon at the highest priority.
Try to garner 1.5k with Hisui and Kor, 1k+ with Beryl. Then the rest try to rack as much points as you can.
Hisui:
Burrowing Owl - I relied on this. It's like an auto landmine. - Circle button
Kor:
Streaking Comet - Circle button
Lightning T.Blade - Right analog stick
Beryl:
Flying Colors - Circle button
Shock-a-Doodle - Right analog stick
Gall:
Burrowing Mole - A weaker and slower version of Burrowing Owl but it will do the trick. - Circle button
Ines:
Blade de Bulles - Circle button
Knee de la Sirène - Right analog stick
Kohaku - I relied mostly on her attacking the balloons rather than using artes:
Rising Phoenix - Circle button
Crimson Twister - Right analog stick