"Everybody dies in the end."
Translation:Alla dör i slutet.
"Alla" is the standard pronoun used for "everybody". "Allihop(a)", "Allesamman" are most often used when addressing a group, and are used for emphasis.
Using "allihopa" here is not grammatically incorrect, but it implies perhaps "everyone in the specific group we are talking about dies", as opposed to everyone in existence.
Indeed. And personally I think that "Alla dör i slutet" sounds like something you might say if you are referring to the end of a book or a movie rather than life itself. In this case I would prefer something like "Alla dör i slutändan" or "Alla dör till slut," even though Wiktionary lists "till slut" as being synonymous with "slutligen," which would just be weird in this case, as you have already pointed out.