Yes, of course they could. Then Satoshi is an intelligence agency, so Satishi is definitely exists.
Did you ever been curious about how opensource software created? Single persons, hackers collectives, agencies and corporations write something and sometimes for whatever reason publish code under some nickname. In any case they are exist.
Of course. Somebody wrote the concept and code. Whoever did that, he/she/they is/are Satoshi. Concept and code can't appear out of thin air.
Could an intelligence agency wrote the code?
Yes, of course they could. Then Satoshi is an intelligence agency, so Satishi is definitely exists.
Did you ever been curious about how opensource software created? Single persons, hackers collectives, agencies and corporations write something and sometimes for whatever reason publish code under some nickname. In any case they are exist.