
We were missing a lot of Jedi appearing in Episode 3, and one of those was Barriss Offee - a Jedi who had a duology set of books written about her! I know people have their favorites of Shak ti (reportedly killed by Anakin during the templte purge) and Aayla Secura who has a 99% chance of being killed by the clone trooper ambush, and Mace Windu who has a 99% chance of being zapped too hard by lightning, falling too fast, and having only one hand to latch onto a speeder with that he most certainly plumets to his doom.
But the one character we do not see is Barriss Offee. In the webstrips, she is reportedly with Aayla at the time -- with her on the same planet, though not necessarily with her in command. However, we do not see her getting killed and I did not see her anywhere on screen. We do see her former master, Luminara, on Kashykkk leading the front lines. We can only assume that she dies since we see her surrounded by clones.
The reason Barriss is such a good candidate is that she just recently became a Jedi Knight prior to the events of ROTS. Prior to that she was a long time Padawan - much like Obi-wan wat to Qui-gon. Furthermore, she was an interesting enough character to star in the Medstar books, where she was a great healer of the clones. I have read all of the EU books during this time line up to the Last of the Jedi book where the closest thing to mentioning her death is Barriss is only briefly mentioned as a name that Obi-wan misses while sulking on Tatooine.
However, this does not confirm her death in my opinion. After all, Obi-wan didn't go looking for survivors really - he fought Anakin and then retreated to Tatooine. In fact, one theme in The Last of the Jedi is how Obi-wan is lost by sitting around doing nothing and feeling sad all the time. More interesting than this is that Obi-wan also finds a former Padawan in this book who is a catalyst in the start of the rebellion.
Let's face it, George Lucas is going to have to come up with some interesting plot lines that can be confined in the 30 years between Ep 3 and 4. A lot of the EU talks about the last of the Jedi helping to start the rebellion, though they're only really catalysts and its the normal people who really should be thanked for standing up to evil. Now, George can't just throw Mace Windu back in our face, he's too powerful - almost beating the Emperor, and would be lame to see him come back and die a second time.
George is going to have to give us stars of this TV show, and they will have to die or go away by Episode 4. We can't fall in love with the TV characters, or people will whine about them not being in the OT. It would be a good move to use some of these lesser known Jedi as good roles in the TV show - keeping a good flow of the story. They can then be killed off by Darth Vader which would fit exactly into the plot line since ole Vader goes around exterminating Jedi who survived the initial purge during this time period.
In terms of plot, Barris would fit right in. Fairly new Jedi Knight barely escapes the clones and flees to some planet where she watches the deeds of the Empire and indications of a rebellion forming. What does a rebellion need? A healer! That would make a huge difference in the beginning when recruiting is low, and loosing rebels to wounds would hurt the cause a great deal.
As noted in The Last of the Jedi, former Jedi/Padawans are great at rallying the troops with their amazing skills in fighting the imperial troops. If there isn't a former Jedi/Padawan in the TV series, I would be very suprised. Finally, as soon as she used her light saber, it would draw the attention of the imperials and Darth Vader. This would create a good overarching plot line in the show where Darth Vader is looking for these rebels and trying to exterminate the former Jedi.
The only down side is that we'd have to see Barriss either die at the end of the TV series or fade into obscurity since she is not in the OT.
Other Questions
Wouldn't Yoda or Obi-wan know if Barris was alive and starting the rebellion? Well, there's no indication in the movies that they knew of other Jedi during that time one way or another. Yoda might, but Obi-wan is far too focused on the wellfare of Luke to go search the galaxy for a few other survivors.
Wouldn't Darth Vader kill these Jedi? Yes - this would allow for cameo appearances of Darth Vader in the TV series. After all, Jedi, Sith, and Darth Vader specifically are huge money markers for Star Wars. Having a few cameos would line the pockets of Fox or whoever produced the TV show.
Wouldn't Barriss or other Jedi be mentioned by people in the Rebellion during the OT?
Not really, let's face it - we see about as much of the rebellion in the OT as we see the Senate in the prequels, maybe even less. Furthermore, if this person dies many years before Endor, then there's be no reason to really discuss it when you're about to go finally kill the emperor. Most likely, only a select few would even know that Barris was a former Jedi (just like in The Last of the Jedi book and that former padawan).
What about Han and Chewie as tie in characters? Well, Harrison Ford couldn't play a young Han, and I really hope they don't take a chapter from Young Indiana Jones and come up with a new younger actor. Chewie is a possibility, and Lando if they want a different actor. Either way, Han and Lando would be children during this time, so I doubt they woudl be here. Chewie is a possibility as a former friend of Yoda, who would be the mutual go between with Barriss.
What about the end of ROTJ and the ghost Jedi, we don't see Barris there! Well, let's face it - the OT and prequels are all around the skywalkers, and only direct interactions get to be ghosts, and even then, ROTJ ghosts are limited to that timeline. Besides, from the point of view of the OT, Barris would be yet-another-jedi-killed-by-vader and not related to any of that plot other then helping getting the rebellion going.