From Wikipedia:

Jehovah's Witnesses believe that a "little flock" of 144,000 selected humans go to heaven, but that God will resurrect the majority (the "other sheep") to a cleansed earth after Armageddon.

I feel like the presence of the headstones and the children more points to the latter belief, that God will resurrect the dead after Armageddon or whatever.

Like, God has resurrected your kid's dead grandpa, straight out of the grave, and now you're forced to deal with your shitty father-in-law for eternity