PEK
PEK is back to normal, BUT , this airport does about 1500 flights a day, & when the afternoon storms roll in, that is when there are 'delays'.
So ?, are they on Air C., T-3, or Hainan air, T-2 ?. Its a looong 14 hour flight with children..., You should be ok in YYZ with a connection to MSP if on time arrival.