YS> I find that kids in schools who offer optional studies rarely take advantage of them and most just do the bare minimum.
The schools I described do not make these “optional”, they are simply online and clearly separate from the yeshiva curriculum. Also, having an additional tutor that could occasionally help/direct the students will make this model even more effective. Avi Chai foundation had several studies several years ago of online/blended studies like that in Jewish schools and have reports written up about it.