are there any sequels of it in the short film genre?
Yes, "A Holiday Reunion"
E.T. the Extra-Terrestrial
On November 28, 2019, Xfinity released a four–minute commercial directed by Lance Acord, calling it a "short film sequel" to the original motion picture, titled "A Holiday Reunion". The commercial stars Henry Thomas, reprising his role as Elliott, now an adult with a family of his own. 
which actress contributed to developing the voice of e.t. the extra-terrestria Pat Welsh
wiki:13389052
E.T. the Extra-Terrestrial [SEP] Short film sequel
On November 28, 2019, Xfinity released a four–minute commercial directed by Lance Acord, calling it a "short film sequel" to the original motion picture, titled "A Holiday Reunion". The commercial stars Henry Thomas, reprising his role as Elliott, now an adult with a family of his own. The story follows E.T.'s return journey to Earth for the holiday season, and focuses on the importance of bringing family together. The commercial utilizes a practical puppet for E.T. himself. John Williams' score from the original film is mixed into the commercial. Spielberg was consulted by Comcast (parent company of NBCUniversal, which itself owns Universal Pictures) before production on the commercial began.