Interesting Idea about switching them pain sounds around the problem is when Luke pushes the hose in Vader's face there is a lot of other sound effects going on. So although it's easy to alter Vader getting knocked down the Hose in the face is kind of baked in.

So it is possible perhaps but would be extremely tricky to pull off for the Hose in the face.

Kershner wanted to make sure that the audience was aware that the android technology allowed for pain and the android parts was seamlessly integrated to the Biology of the user.

Something else I noticed is that there is no melee hit sound (or it's really subdued in the mix) when Vader get's knocked down. I wonder if the sound of Luke kicking Vader from ROTJ could be used but have the pitch and volume altered and keeps continuity with the next film of what Vader sounds like when Luke hits him.

I tried the Respirator malfunction the sound I made was fine it comes off like a joke which I had a feeling it might. :)

The Vader Breath at the very end of the vivaldi trailer is the most epic breath Vader ever took so If Ady can find a place for this one somewhere in the film I would be Happy to hear that one especially but I don't have any suggestions of where it could or should go.