Believe me I don't like it either, I'm just hoping we get some SR1 and 2 homies with the mission DLC (read Lin)
Oh, most of the hidden audio was cut from the game or replaced with other characters.
Hopefully we will see it as DLC but may be wishful thinking.
They are big on reuse... I can say Donnie wont show up in DLC for sure though, His audio file he was abducted early because the zin thought he would know how to take out the saints for whatever reason, he ended up escaping his pod and the boss finds him roaming around zinyaks ship. Oleg, Josh and Viola all died together. The only two people we don't know about zemos and angel.
I have also read that enter the dominatrix will be some type of "directors cut" of ideas for SR 4 though... So not sure how well that's going to go down, have to wait till October and find out.