Well the Season 3 trailer showed as a lot of things.. Here is a brief description of what we have install for each character.
Please note that possible spoilers for the first two episodes of Star Wars Rebels Season 3
Main Characters
Ezra Bridger - Ezra now sports a new hair cut - its now short. Dave Filoni did this because fans were not keen on the Aladin hair but now they are not happy with his new haircut. Ezra having a green lightsaber follows continues the same parallels of the original trilogy, as Luke has a green lightsaber in that film for the first time. Ezra is turning to the dark side - far more gradual than Anakin. He is using the sith holocron (made of pure evil) to do 'good' in his eyes. Although Ezra does loose the holocron in the opening episodes to the Bendu he is still very arrogant. Ezra is now a lieutenant in the Rebel Network and since Kanan is now blind he is leading the missions
Kanan Jarrus - Kanan now has a beard and he has an adapted jedi temple helmet to go over his eyes. In the opening episodes Kanan remains on his own meditating before the Bendu makes him see sense. The trailer sort of indicates that Kakan gets his eye site back.
Hera Syndulla - Hera now has a badge to indicate her role as captain of the pheonix squadron. There is still more to it with her father left to tell.
Sabine Wren - Sabine styles a third new hair colour. This is one that the actress wanted for Season 2 but now she has it - the colours are white and purple. Sabine is going to get a jetback and the darksaber that previously belonged to Pre Vizla and then Darth Maul. At the celebration, the actress of Sabine teased that we are going to see some of her family. Sabine has previously mentioned that her mother was in death watch and that she is a member of the house of Vizla. Sabine is going to go on a big mandalorian journey, meeting several mandalorian groups such as the protectors of Concord Dawn, Death Watch and Imperial Mandalorians. She may also meet some pacifists. Sabine's role in the imperial academy is also going to be explored as well. Filoni has previously said in an interview that Sabine's role in the Rebels story is as crucial as Ezra's.
Garazeb "Zeb" Orrelius - Zeb has lost some of his arm armour. This is to make is design more simple. It isn't because of costs but because the production crew want him to look more like the aliens in A New Hope.
C1-10P "Chopper" - Chopper is likely just to be his usual self.
Recurring Characters that we have seen before
Rex - Rex is likely to be more involved now that Kanan is blind. I imagine that he is going to go on the missions that the Ghost crew take. The trailer shows Rex get back into his old armour and fighting battle droids.
Commander Jun Sato - Sato is going to be important to link our group to the bigger picture. General Dodanna, a general from a New Hope, has previously been mentioned already. The trailer sort of suggests that Sato is going to die.
Agent Kallus - In season 2 we were hinted that Kallus could defect and join the Rebels. In the trailer for Season 3, Kallus is nowhere to be seen. Some people have commented that Kallus is in the trailer wearing non-imperial armour but I think that they are getting confused with Fenn Rau - the Protector of Concorned Dawn. Kallus is in Season 3 as he is in the very first episodes but I think he going to be less involved.
Maul - Maul was introduced right at the end of the last season and made a big impact by kill all three inquisitors and blinding Kanan. Maul is not in the first two episodes and I don't even think he is mentioned. Maul is also not in the trailer very much. This is surprising as Filoni has previously said that Maul is going to be the main villain of Season 3. The trailer and the first two episodes indicated that it is going to be Grand Admiral Thrawn - more on him later. I am slightly annoyed by this that they are introducing yet another figure into the show but are forgetting about those they have already added in. Maul is still focused on trying to turn Ezra to the dark side.
Admiral Kassius Konstaine - This character is just a bit pointless, especially now they have a grand admiral. I can't really see Konstaine staying for too much longer.
Hondo Ohnaka - Hondo is in the first two episodes but Azmorigan is not - therefore we still have more Ohnaka to go. Hondo is a popular Clone Wars character and seems to be becoming as much as a rebels character as he was a Clone Wars charcter.
The Presence - This is the sith holocron's voice. People who have seen the first two episodes would assume that the sith holocron is gone for good now it is in the hands of the Bendu. This is wrong because we see Maul and Ezra with this holocron in the trailer. Filoni has also said that this character is very important.
Cham Syndulla - Cham leads one of the most successful rebel cells and is Hera's father so I expect to see him again. We also know that Thrawn is a bit of a problem for Cham.
Fenn Rau - Fenn Rau is a mandalorian so there is his link to future stories.
Star Wars Character in Rebels
Rex, Maul and Hondo have all been mentioned already
Darth Vader - Vader was a big part of Rebels Season 2 but like Maul and Ahsoka seems to have been forgotten about at the beginning of Season 3. Vader is also completely absent from the trailer (although the trailer is only for the first half of the season). I don't think they can just leave Vader out of the picture but then I thought that about Tarkin at the beginning of Season 2 and they did just leave them. I think we will see Vader again because I am nearly 100% sure that there will be a Vader V Maul lightsaber duel.
Ahsoka Tano - Ahsoka, like Vader, played a big role in the second season. Filoni has said that Ahsoka is not done yet but he didn't say whether she would be in season 3. I doubt that she will be - for own safety.
Lando Calrissian - Lando appeared as a guest in the first season and made a brief appearance in the second. Billy Dee Williams who acted and voices Lando has already said that he is in at least 3 episodes of Season 3. This is more plausible as it doesn't look like Lando is going to be in Episode 8, therefore Billy Dee Williams has more time on his hands.
Grand Moff Tarkin - Tarkin had quite a big role to play in Season 1 but was then cast a side for Season 2. Takin is in the first episode and the clip of him in the trailer is in the first episode so there is no indication if we will see him again. Filoni has said that Rebels in Season 3 is going to tie in more with A New Hope and Rogue One - both of which have the Death Star as a large theme. Therefore I imagine we are not done with Tarkin.
Yoda - Yoda is no where in the trailer but I believe we will see him again. We are sill not a where why Yoda sent Ezra to Malachor. That I believe we will find out.
Bail Organa - As we are seeing the Rebel Allience grow I would not be surprised if Bail Organa turns up again. I also believe that Mon Mothma might as well.
Princess Leia Organa - When a member of the production crew was asked if Leia was in more than one episode they said one episode this season. Therefore it is a possibility that we will see Leia in Season 3.
Wedge Antilles - Wedge is going to become the next Star Wars star to join Rebels. He is a Imperial Space cadet who goes rogue.
New Characters
Grand Admiral Thrawn - Now when I say new Thrawn isn't exactly new. Thrawn is a character introduced in the Thrawn trilogy of books written by Timothy Zahn. They are the most successful books of all of Star Wars. Many fans were sad when all the events that take place in the books were made non-canon by Disney. This meant that one of the greatest Star Wars villains was now non-canon. Now he is canon. Thrawn is back and also is Timothy Zahn is writing the new canon book Thrawn. Thrawn is a dangerous villain because he looks into the background of his opponents that is how he finds their weakness. Finally Star Wars fans can see how Thrawn and Tarkin interact.
Governor Pryce - Pryce isn't exactly new either as she has bee mentioned a few times in the previous seasons. A Pryce is the governor for Lothol we can expect that Lothol is sitll relevent. Filoni has said that we will explore why Lothol is so important to the Empire
The Bendu - The Bendu is somewhere inbetween the light and the dark. He is also voiced by the 4th Doctor Tom Baker. As the Bendu now has the sith holocron I would expect the Bendu to do something not that great with it.
