(Since all of that cannot be covered in a 90-word Q&A answer, I’ll focus on the main themes.)
Everyman marks a transition between the medieval morality play and Elizabethan drama. Although Everyman is a type, representing humanity in general, rather than an individuated three-dimension character, he does develop and follow a plot line. In his search for companions to help him face his final judgement, he gains a truer knowledge of self and world than mere accumulation of facts.
The main theme of the play is the transitory nature of all worldly pleasures and goods, for none of those can help man faced what lies beyond death. He allegorization of the worldly goods as companions who leave Everyman in his time of need dramatizes the morality of the play; the steadfastness of good deeds and the church provide a dramatic counterweight to the ephemerality of all the other activities and acquisitions of the protagonist.