The Jedi Didn't Save
Oppo Rancisis, Coleman Kcaj, Ka-Moon Kholi, & Selrahc Elous. Oppo Rancisis, Coleman Kcaj, Ka-Moon Kholi, and Selrahc Eluos were all names on a list of known survivors compiled by the Inquisitorius, as shown in the Darth Vader comics.
No, Anakin had gone over to the Dark Side and was totally beyond redemption when he led the Jedi Temple raid. None of the Jedi, padawans or younglings at the Temple were spared. Most likely Grogu was rescued by someone before the raid went down or else he wasn't any longer there.
Sadly no. Reva saw her fellow younglings die all around her, Obi-Wan and yoda saw the hologram recording of Anakin slaughtering the younglings, and we (the audience) see the dead younglings on the jedi temple floor in Revenge of the Sith. Palpatine likely sensed Padme's death through the force.
The canonical comic Star Wars: Darth Vader #7 confirms the younglings' deaths caused Anakin grief, self-loathing, hatred and pain, fueling his descent even further into the dark side. Those negative emotions also power the dark side, meaning Anakin likely felt stronger as he killed the younglings.
Over the years since the Youngling massacre, and even sometime before, Darth Vader has regretted killing the Younglings, recognizing that it was the most terrible thing he had ever done.
Did Vader let Ahsoka live? Initially no. Vader killed Ahsoka in the temple because Ahsoka couldnt let go of her guilt over Anakins turn into Vader. She felt responsible for leaving him when she left the Jedi order.
Grogu will likely never become a real Jedi. After being given an impossible choice by Luke Skywalker in Boba Fett Episode 6, Grogu chooses to leave Yoda's lightsaber behind and join his surrogate father Mando (aka Din Djarin) once again.
Vader held respect for Tarkin which is clearly shown and the only case in which Tarkin outranked Vader would be the case in which Vader was in the Death Star or within Tarkin's Oversector which he likely was as Tarkin was Grand Moff of the Outer Rim Oversector, the largest one.
Because he was not an active member of the Jedi Order during Order 66, Infil'a escaped execution. Some time later, he faced the Sith Lord Darth Vader wielding a green lightsaber. Infil'a put up a fierce fight against Vader, almost killing him by throwing the Sith Lord off of a cliff.
This pushed Fett over the edge and resulted in him killing five Jedi with his bare hands.
Admiral Ozzel : [appearing onscreen with Captain Piett] Lord Vader, the fleet has moved out of lightspeed and we're preparing to... Darth Vader : You have failed me for the last time, Admiral! Captain Piett?
Order 67 was an order requiring clone troopers to begin dancing. During the Battle of Utapau, Darth Sidious accidentally executed Order 67 when he meant to use Order 66. Just after the order was executed, Cody and his troops began dancing.
Gungi was a male Wookiee Jedi Padawan who trained to become a Jedi in the Jedi Order during the Clone Wars.
Ahsoka became aware of Darth Vader's presence in the Star Wars Rebels Season Two premiere "The Siege of Lothal." She seemed to have suspicions about who the Sith Lord actually was, but she didn't uncover the truth until "Shroud of Darkness." She had a vision while visiting the Jedi Temple on Lothal and realized Anakin ...
Grogu is not in the sequel trilogy, so he must have died sometime before the beginning of Episode VII. Maybe Kylo Ren killed him when Ren destroyed Luke's academy, maybe the First Order found and ended him, or maybe he died on a Jedi mission.
Darth Vader taking the saber represents Anakin's love for his first spiritual child, Ahsoka. It echoes the way he addresses her by name in Rebels' “Twilight of the Apprentice,” letting Ahsoka know that her former master is still in there somewhere.
1/15 Luke Skywalker
Having faced his father once before, Luke was familiar with his tactics and used the force to gain an upper-hand. In Star Wars Canon, only Luke Skywalker can be acknowledged as the one who truly defeated Darth Vader.
Whilst Jocasta wasn't exactly known for skills with a lightsaber or the Force, she did sit on the Jedi High Council at one point, and Palpatine feared her because of her knowledge.
So in summary, by the time of the sequel trilogy the galaxy at large would have been aware of the truth of Darth Vader's identity (or at least the information would have been out there), but it was kept secret from the time of Vader's fall in Revenge of the Sith through six years before The Force Awakens.
How did Kylo Ren obtain Darth Vader's mask in "Star Wars: The Force Awakens"? It's believed it was obtained by Luke Skywalker when he was collecting Force artifacts throughout the galaxy and kept at his Jedi Academy. When Kylo Ren burned it down, he took the mask, beliving it was his by right of lineage.
To give a quick answer, yes, Darth Vader turned good at the end of the Star Wars Skywalker Saga. He fulfilled his destiny by bringing balance to the Force. Keep reading to learn more about Anakin's life, Darth Vader's redemption, and the prophecy he fulfilled.