When Harry Met Mary, Ivan, Charlie and Gary

When Harry, Gary, Mary, Charlie and Ivan exchange pleasantries the results are rarely pleasant except for the rare few that adopted a compromise with whom they spent the most time. For those who tried to befriend the quintuplet simultaneously may dare to say that our honorary guests became a mixture of lethal standards. Such lethal standards that if one were to get word of their whereabouts, their chaperones would desperately seek to evade capture for the facilitation of their frivolous friendship.

Who are our guests?