[Eng] Tsunomaki Watame - Little Bow Sheep

There were a few references I'm unfamiliar with. Really want to know what that song at the end is from.
Harp model made by reddit user Castform5:
/ castform5
From Watame's 8.5.20 Minecraft stream (around 2:25:00):
• 【マインクラフト】砂を取って焼いて建築する！...