There's a few Youtubes of the assemblies in Indonesia at the same time
This one looks like young children singing before delegates. They've gone overboard in dressing up their children in the same clothes. The girls have dresses in different patterns made out of the same material, including belts and headpieces. See 2.12 and at 14.10 even the mothers are dressed up in the same material as they parade their child to sing in front of the microphone for a few seconds.
https://www.youtube.com/watch?v=qHEstv_TacM
The next video includes a comment that this years convention was special as all conventions were held at the same time in Indonesia, from 17 to 19 November. It shows them waving their phone lights but no dancing.
https://www.youtube.com/watch?v=ZEenzn1vUCc
The next video shows male and female attendants welcoming guests at 1.06 and dressed in the same costumes. Then at 2.47 it looks like a family dressed in the same material.
https://www.youtube.com/watch?v=vjDAlPnyfZg
In the following video it looks like these JW ladies are dressed up as bees for their special conventioners.
https://www.youtube.com/watch?v=5XsOI2qdsEs