I think what they do now is have a performer do the lines on the set, and then the normal performer comes in later to do the voice over. In MCT Dave played Rizzo in one scene at the end with Kermit, but they forgot to go in and have Steve redo the lines.
In MFS, they had performers do characters and then have the lines dubbed as well. Thats what they did with Fozzie, Sam, Piggy, and Animal. Frank came in and redid the lines while others performed the characters.
On TMS, I think they used pre-recorded lines live because it wasn't nearly as easy to drop in sound back in the 70's. This made for some weird looking speech.
In TMM with the song Rowlf and Kermit did, I think they just redid all the dialog in a studio as they do all songs.
No matter how it's done, there are many ways to have characters by the same performer interact with each other. Bobo could easily talk to the Chef or Pepe especially with digital recordings.
In MFS, they had performers do characters and then have the lines dubbed as well. Thats what they did with Fozzie, Sam, Piggy, and Animal. Frank came in and redid the lines while others performed the characters.
On TMS, I think they used pre-recorded lines live because it wasn't nearly as easy to drop in sound back in the 70's. This made for some weird looking speech.
In TMM with the song Rowlf and Kermit did, I think they just redid all the dialog in a studio as they do all songs.
No matter how it's done, there are many ways to have characters by the same performer interact with each other. Bobo could easily talk to the Chef or Pepe especially with digital recordings.