Questions

Don't know why he couldn't get out. Don't know why the ghost killed the people but I'd guess that he wanted a mother just for him. He killed the couple away from the "house". The last one laid down next to him and she wasn't surprised when he touched her.

I don't know if you saw a version that had subtitles for the written material but the one I did had very little. I think my ability to follow and understand the movie was negatively impacted. If you saw a version where the written material was subtitled, let me know?

My guess is the people transporting it made sure the lid was on there real good before leaving the gas station.

I think the ghost child was getting revenge for the woman's pain that they caused her. She looked a lot like his mother and she was emotionally distressed, so he was drawn to her.

Benni's father mentioned that Benni had diabetes, and if he didn't get food and insulin regularly, he would lapse into a coma. That's probably how he died.