Different story arc then the Civil War. The Spiderman who died was the Ultimate version not the main stream Spiderman. The Ultimate storylines are the ones that the Marvel Movies are based around. Example, they had an Ultimate Spiderman storyline going on when they were filming Spiderman2 where the director saw Spiderman fighting Doc Oc and filmed that rather then the actors in the film.
The Ultimate storyline has always been much grittier then mainstream storylines. People die in them quite frequently and no they don't come back several issues later. Here death is pretty permanent thing.
Every single character can die and then be resurrected with no questions asked. I have the 1 off issue called "Punisher Kills the Marvel Universe" which as you can imgine from the title has the Punisher killing all of the major Marvel characters but they continued on as though nothing happened. How many times has Galactus been destroyed and then restored? You gotta love comic books!
Yup, in both Ultimate and Mainstream comics, Aunt May is still alive. Mainstream is due to a deal Parker made with Mephisto. And yes, aging in Marvel is greatly reduced, not Simpsons reduced but close to it.