Numbers 1,2,3 were inventions by the Turks so they wouldn’t have to reveal that they had ‘bugs’ all over the Saudi embassy.
That would not explain why they don’t release street cam footage. It would not conclusively “prove” that Khashoggi never re-emerged but it could demonstrate that he did not re-emerge within a certain period of time, e.g., the first 30 minutes or 60 minutes.
ALso, it’s not an embassy but a consulate (the embassies are in the capital of Turkey, Ankara).