When the Robot says "Friends, Will Robinson" the hatch is open, so the room is in a vacuum, and there would be no air to transmit the sound of the Robot's voice to Will.
At 09:21- Don tells John to start unscrewing four "hexagonal" bolts but John is unscrewing "button head" bolts.
Maureen calls Dr. Smith "Judy", but she never revealed her real first name to her. She said her name was Jessica, her sister's name whose identity she stole.