Yeah. Also, since you play the game from the point of view as Roxas, I guess they also felt that since Riku squeezed Roxas into unconsciousness, that part was unnecessary to show. Since, as Roxas, there's no way you'd know it happened.
As for the whole short scene with DiZ and Riku...
(Riku: He could feel Sora...
DiZ: Ridiculous! A Nobody can't feel anything...)
Yeah, that was just shown to link up to the KH2 scene Sign described. By the way, that scene occurs when you're going into the depths of the Old Mansion and find the computer. I think.
Also, my quote up there may be wrong, but it's close enough.
Oh, and welcome back!