I would say it's a simile because they are comparing with using the word "like". They are comparing there howling to the wolves.
My home in the city would likely be a lot more expensive versus in the village/countryside
It most likely gives a negative connotation because something being on fire is usually not a good thing. So if your marriage is on fire it is probably not going so well and may need to be put out or in other words Divorce
I am not sure what section you are referring to but probably because the sun is a star.
Do you have to pick one? cause if so i'd say diagrams and headings