Sabé will be killed by Darth Vader
The story of the series is set after The Empire Strikes Back and before Return of the Jedi. In the latter film, Sabé is nowhere to be seen. Why? Possibly Darth Vader will end up killing her. Perhaps Sabé will end up discovering that he's Anakin Skywalker and was responsible for Padmé Amidala's death or Vader will find out about Sabé's feelings for Padmé and will get jealous, leaving Vader with no more option than kill her. After all, this happens with almost every character who crosses paths with Vader and displeases him. Tonra will make an appearance
Sabé's appearance in the series ties into the epilogue of Queen's Shadow. The last time we see Sabé in the novel, she decides to change her identity alongside Captain Tonra to investigate about how Padmé exactly died. As Sabé has made an appearance now in the series, it's possible that an aged Tonra may be making an appearance in further issues. Maybe he hasn't appeared yet because he needs Sabé to lure Vader into a trap?- If Tonra appears, however, he can be potentially Doomed by Canon like Sabé as mentioned above, given his absence in Return of the Jedi.
Emperor Palpatine was not first killed in Return of the Jedi
An In-Universe explanation for Emperor Palpatine's change of look in the original trilogy. In the post-2004 editions of The Empire Strikes Back, Palpatine looks exactly like he does in the prequels. However, in Return of the Jedi, Palpatine looks different. As The Rise of Skywalker explains that Palpatine was revived as a clone following his death during the Battle of Endor, then there's a possibility that it wasn't the first time Palpatine died.The theory is that by the end of the series, Darth Vader discovers that Palps may have been the one responsible for Padmé's death. Thus, in a fit of rage, Vader kills his master. Nevertheless, instead of dying, Palpatine resurrects himself by sucking some of Vader's life force. This can also explain why Vader barely used the Force in Episode VI.
The Naberrie family will appear
Unlike the Star Wars Legends continuity, we never see what happened with Padmé's family following the events of Revenge of the Sith. The publisher's summary of the next issues have advertised that Darth Vader and Sabé will be coming back to Naboo to look for answers and even visit Padmé's tomb. Maybe we will see them interrogating Padmé's parents, sister and niece?We will see how Vader gets his Sith wayfinder and entrusts it to the Eye of Webbish Bog
In The Rise of Skywalker, it's shown that Darth Vader had a Sith wayfinder which led to Exegol and which he had stored on Mustafar. The Novelization reveals that a swampish spider-like creature known as the Eye of Webbish Bog, which appeared in a Deleted Scene, guarded it, with the Eye mentioning that Vader entrusted him to guard his wayfinder. It has been recently confirmed
that the series will have some connections to Episode IX, so maybe we will discover here if the Eye was telling the truth to Kylo Ren or not?Gregar Typho's crush for Padmé Amidala will be recanonized
In the Star Wars Legends book trilogy Coruscant Nights, Captain Gregar Typho, whom we first saw in Attack of the Clones, was depicted as trying to avenge Padmé Amidala due an unrequited crush he had on her as well as Anakin Skywalker, whom he thought to have been killed along with Padmé by Darth Vader. Given that Typho has appeared in the third issue, then maybe it will be recanonized his unrequited crush towards Amidala to give him a reason to join the Amidalans.Vader will spare the Amidalans.
Given Olié somehow survived being stabbed in the shoulder and Vader opted to force shove the Handmaidens away instead of slicing any of them, the arc could end with Vader having a Heel Realization about Padmé and ends up leaving the Amidalans alone.