oh, I thought you are looking for music for CHILDREN, but if those are middle school kids I think they would listen typical hits from single chart top 10 or whatever
for example, you can check here what is a "thing" in Hong Kong now:
https://www.kkbox.com/hk/en/charts/c...ng-latest.html
(especially G.E.M., JW, Gin Lee and AGA are one of the most popular young singers in HK now)
or try this chart based on itunes:
https://www.hotmusiccharts.com/hk/itunes
hope it helps a little bit