I think the three yukkuris here are the children and the father Marisa left to get help and didn't come back. In the next few pages, I think the big Marisa is the big sister.
Day 2 Mother Reimu: "Yuyu...can't take it easy..." The unlucky part, the rain has started.
koMarisa: "Da je!" koReimu: "Yunya-! Myamya-! Big Sis Marisa: "There's no need to worry here!" The lucky part, the children have escaped from the rain and the rain the place and tree where Mother Reimu is hanging.