Ans 1)A cameo role or cameo appearance (often shortened to just cameo) is a brief appearance of a known person in a work of the performing arts, such as plays, films, video games and television.
Ans 3) bit part
Ans 5) A character actor is one who predominantly plays a particular type of role rather than leading ones. Character actor roles can range from bit parts to secondary leads. However, character actors often play supporting roles, for characters not subject to a major change or revelation in the course of the plot, and whose role is less prominent.