+0
Are theatrical performances, dramas, plays included in 'literature'?
+0
Yes, part of what is called "theatrical literature":
<>Google books:

<>736 on "theatrical literature"
Comments  
TakaAre theatrical performances, dramas, plays included in 'literature'?
Yes. And there's also "music literature", which includes symphonies, concertos, operas, etc.
CJ
 Marius Hancu's reply was promoted to an answer.