I don't count Jaba's appearance in A New Hope so he doesn't count. I too only have Luke, Leia and Chewie for 4 movies.

3 movies is a bit harder, since anyone who was in a full trilogy counts as well as anyone who was in two movies of one trilogy and one movie of the other (such as Boba Fett). In particular, random Jedi Council members make this hard. Like the conehead one. Also, charlie you forget an obvious character from the OT! And the Viceroy and his assistant.

Two movies is almost impossible to anyone who isn't a super hardcore fan. I think Bail Organa is only in two movies, unless you count his screams from A New Hope that Obi-Wan hears.