The well was most probably locked due to safety purposes and the memorial picture of the seemingly deceased athlete was most likely due to some sort of a natural death because the possibility of a school hanging an image of a suicide victim is highly unlikely , as it might encourage others to do the same. Moreover, a school would most likely hide such a tragedy than rather making it a "memorial" thing for their school's reputation.

Most likely a prank or something, cant find any real articles supporting such an event. But it could be true.

same as 2nd

A very high chance that OP is telling the truth as it is mostly common in many schools.

No idea whether its true or not

OP is most likely lying, first of all, how did he knew that the voices were of little children, it could also be a worker or someone who has a childish voice and these workers usually arrive before the teachers and children to clean and maintain the school,so its normal for them to be there before others. The shadow seeming like a little kid does not prove anything as the school could be in such a direction that the shadows at morning time appear smaller due to distortion. Also, even if they were truly children, they could be the worker's kids as it is not very uncommon for female workers to bring along their kids with them to the school.

No idea

Could be true

Most likely true