Wow, this thread is still up? Neat. I had some spare time and thought I'd go through some of these.
Remember, the Exile's return has been posted mostly everywhere in the "coreward databases," according to HK-47. Though G0-T0 was looking for the Jedi, he was merely acting upon the information he had access to in those databases. Atris was the one that broadcast the information. One definition of insanity is doing the same thing over and over agin expecting a different result. She did it with releasing the Exile's "homecoming" information and also she tried it before - in order to draw out the enemy at Kattar. Since G0-T0 knew about the Exile's return, who's to say Green didn't have access to the same information? Then again, maybe Admiral Onasi just told him that the Exile is an Exiled Jedi - as they were working together as well.
T3-M4 was sent out by Bastila (or Carth) to find anyone that could help Revan. Who's to say that T3-M4 didn't seek out Kreia - his/her former master? T3-M4 obviously had the ship - the navicomputer can only be used by him, if you all recall.
Additionally, we do know pretty much every major figure (in the game) knows the Exile is coming back. Why wouldn't Kreia know too? Put T3-M4 searching for Kreia in the Ebon Hawk - and Kreia searching for the Exile using the information sent out by Atris and it isn't that much of a coincidence.
If you take what I said earlier as fact, that would Kreia lying.
That bothered me too. But there's very few continuity mistakes. I do recall one cut line saying Revan destroyed Telos even though it was well established the Malak did that in the first game. (I think the cut line was originally said by Kreia as I recall re-splicing it so she said Malak instead of Revan.)
Perhaps a quote from Chris Avellone himself might explain that . . .
See previous answer. Additionally, in his first conversations, he does say he doesn't want to talk about the war if you don't mind, which seems to suggest that at some point you'd likely be talking about it more in some detail. (Greater detail than what wound up in the game files anyway.)
I think I may had a thread about that somewhere . . . oh yes, here.
In Sion's defense, he can bring himself back from the dead over and over again, as long as you don't erode his will. Since they cut out M4-78 pretty early, it stands to reason her character was fully developed yet. (Hell, even M4-78 doesn't have any lines voiced or wirtten in the game.) Perhaps the game maker, didn't want to hear the voice actress do even more lines? Grey DeLisle also performed the voices for Brianna and the other Handmaidens. (Ok, for the last part - I kid, I kid.)
Echani were also in KOTOR1. One is being hired by the Sith in a cantina on Manaan - the same cantina that the Selkath asks you to do a mission to find missing Selkath children. Echani is both a near-muahm species and their unarmed martial art. In this case: Wookieepedia is your friend.