As far as Kanan knew, Anakin had died defending the temple during Order 66. He didn't have any sort of connection to him, so he couldn't feel that Anakin was behind the mask. Ezra didn't even know Anakin, had never seen or heard of him until Ahsoka showed him a holocron.
Well, he most certainly knew of Anakin. Anakin was one of the best known Jedi at that point, and he was definitely the type of person that a young pre-teen boy would look up to.
Since Obi-Wan Kenobi on Disney+ showed that the Inquisitors know about Darth Vader's history as Anakin and his ties to Obi-Wan it means that Palpatine chose to let his apprentice's apprentices in on their master's mysterious past, or Vader flouted The Emperor's wishes and told his trusted Inquisitors about his time as ...
Reva knows that Anakin Skywalker is Darth Vader because she was one of his targets—a child—during the Order 66 killings that took place during the events of Star Wars Episode III: Revenge of the Sith.
In Canon. So who knew that Darth Vader was actually Anakin Skywalker in-universe? It was just as secretive as in real life. Obviously, Sheev Palpatine, Obi-Wan Kenobi, Yoda, Bail Organa, and R2-D2 knew the truth about Vader's identity, as made obvious in Revenge of the Sith.
During Palpatine's reign as Emperor, his apprentice's true identity was kept a secret, leaving only a few Star Wars characters aware Anakin was Darth Vader. Besides Obi-Wan, Master Yoda also knew the truth, as well as Ahsoka Tano, R2-D2 and C-3Po, and even Senator Bail Organa.
R2-D2 was present when Padmé gave birth to Leia and Luke, so he knew Luke was Anakin's son – but what he didn't know was that Anakin became Darth Vader. In addition to that, Anakin's fall was surely a painful event in R2-D2's life, one that he definitely wouldn't like to remember or even talk about.
Darth Vader didn't learn he had a daughter until Return of the Jedi, when he stood before Emperor Palpatine. The Emperor's power probed Luke's mind, attempting to goad him to fall to the dark side, and he discovered Leia's existence. "Sister," the Emperor taunted.
Padmé was well aware that Anakin had committed dark crimes that would've started his fall to the dark side. He even confessed to her that he had massacred an entire Tusken Raider village to avenge his mother, leaving no one alive.
Jocasta worked in the Jedi Archives for decades, and Sidious believes that her precious knowledge will prove useful. A security robot in the Archives identifies Darth Vader as Anakin Skywalker within earshot of Jocasta, and she is shocked.
Yoda didn't specifically know how this would go down, or to what degree Anakin would cause it to happen, but he was playing a much longer game by Revenge of the Sith, and that's at least, in part, explained by Yoda's Force connection with Qui-Gon's spirit.
Star Wars Rebels lead creator Dave Filoni even admitted that Maul and Vader were meant to have a fight, but he felt it would take away from the battle with Ahsoka. But as things stand, Star Wars not only lacks a fight between Vader and Maul, but the two have never even spoken to each other.
Heartbroken, Ahsoka realizes — or maybe fully accepts — that her former friend and teacher has suffered a fate worse than death, and that Anakin is, in fact, Darth Vader. But Ahsoka finally meets Darth Vader face-to-face in the Season 2 finale.
While Ezra faced his own trial in the depths of the temple, Kanan communed with Yoda, who warned him that this was a dangerous time for master and apprentice alike. Kanan promised his old teacher that he wouldn't let Ezra lose focus the way he once had.
Kanan Jarrus
Yoda contacted Kanan through the Force whilst Ezra was being tested in the Lothal Jedi Temple. Whilst talking to Kanan, he told him how he should believe in Ezra. Yoda and Kanan also knew each other during the Clone Wars when Kanan was still called Caleb Dume.
Obi-Wan Kenobi
Kanan had a Jedi Holocron that contained Obi-Wan's message; regarding the fall of the the Republic and that the surviving Jedi must go into hiding until the time was right for them to come out of exile, it is unknown if the two had met or knew each other.
Wait, Did Yoda & Windu Know About Anakin's Secret Relationship With Padme? It's possible that Jedi Masters Yoda and Mace Windu always knew about Anakin Skywalker's secret relationship with Padmé Amidala, and one particular Star Wars: The Clone Wars episode provides proof.
Star Wars is finally exploring Leia's emotional reaction to the revelation Darth Vader was really her father - as her identity is transformed. Star Wars has finally revealed Princess Leia's reaction to learning Darth Vader was her father.
It's not shown, but it is clearly insinuated that Anakin killed the younglings. This is confirmed later in the movie when Obi-Wan informs Padme that Anakin killed them. Both are torn apart with hurt and confusion, trying to make sense of something so terrible. How could Anakin do such a thing?
What would happen if Darth Vader came across R2-D2 and C3PO? He came across Threepio on Bespin. He either didn't realize it was the same protocol droid or figured he'd been memory-wiped so FUNCTIONALLY wasn't the same droid and didn't care.
However, Leia's strong-mindedness during Vader's probe denied him the opportunity to discover she was his daughter. That serves to justify Vader's lack of awareness of his connection to Leia, although, perhaps, not as satisfyingly as if Lucas had planned for the relationship from the beginning.
Perhaps, Darth Vader just figures that this is another protocol droid and not C-3PO. Obviously, C-3PO does not recognize Vader because his memory was wiped at the end of Revenge of the Sith.
The base assumption of why Obi-Wan doesn't remember R2-D2 -- in light of the prequels -- is that Obi-Wan is feigning ignorance in A New Hope to downplay the importance of the droid's arrival.
In the material around the film from the Legends timeline, it's established that by the end of Star Wars: Episode III - Revenge of the Sith, Kenobi was one of the characters who knew Anakin's Sith name was Darth Vader. However, what he didn't know was that he was still alive after Mustafar.