Episode 10 has a Nature Vs Nurture theme which shows why the characters are what they are today. Satanichia's and Vignette's parents are present throughout the episode meaning they are present in their lives before leaving to Earth. Based on the personalities seen, Vignette's and Satanichia's parents were joyful or downright bizarre but has enough parenting skills. Hence, the two demons were raised properly or for Satanichia's case, she was rendered harmless. However Gabriel's and Raphiel's weren't present in the episode meaning that due to lack of parental guidance and combined how strict the rules were in Heaven, the two angels weren't able to handle most of life on Earth and unable to restrict themselves once they entered into temptation.
The animals in Hell are an interesting concept as judging by Chappy's size, its following the top of the food chain. The animals might be reflecting the animals on Earth. Chappy might be bigger than the average dog but Chappy is just reflecting what a real world dog look like in Hell. As for Alexander, he's reflecting an animals basic in homes, a house lizard.
What might have led Zelel in becoming aware of Gabriel's falling is probably during the time a demon (Satania) infiltrated the port where Gabriel was. Zelel might have went straight there worried that her sister might be in danger. However, she instead get informed about the contraband Gabriel was secretly shipping.
It seems strange that the weather just so happens to be better at the same time Satania finds a frog, the one thing Raphiel is afraid of. However considering who runs the skies, it isn't wrong to say that a certain deity wanted to help Satania out in punishing Raphiel.
