The painting on the wall of the Jedi Temple are of the Father, the Son and the Daughter of Mortis, as seen in The Clone Wars series, season 3, episodes 15, 16 and 17.
Minister Hydan was originally planned to be the same character as Vaneé, the elderly attendant seen in Darth Vader's castle on Mustafar in Rogue One: A Star Wars Story (2016).
Although Hera has worn a pair of goggles on her forehead since the start of the show, this is the only time she is seen wearing them over her eyes.
Prior to the imperial minister asking for the floodlights to be switched on, a tannoy announcement is heard which closely paraphrases the announcement in Close Encounters of the Third Kind at the rear of the Devil's Tower in anticipation of the arrival of the UFOs - "... and look out for static charge."
The identity of the biker scout that Ezra disguises himself as is LS-412. 412 is the area code for Pittsburgh, PA/Allegheny County. Dave Filoni, creator and supervising producer of Star Wars: Rebels (2014) is originally from Pittsburgh.