Is it permissible for a lone worshipper behind the row to pull someone from the row to pray beside him, or should he wait until one of the worshippers in the row makes space for him?

The worshiper should wait until someone comes to join the row if the row is complete. He should not pull anyone into the row. He should enter the row if possible or pray to the right of the Imam. The joining of discerning children in the row is valid. As for non-discerning children, their ruling is the same as that of a person praying alone behind the row, whose prayer is invalid. If one fears missing the prayer, finds no space, and no one comes, he should pray behind the Imam, and his prayer is valid, in accordance with the verse: "So fear Allah as much as you are able."