Today I saw that a user was suspended and his reputation went to 1, but now I go to the Suggested Edits review queue and I see that the user has 3 reviews.
Can a suspended user make reviews?
Since the user was not suspended at midnight GMT (the timezone used for the Stack Exchange day), it is probable those are reviews made before the user was suspended.
Suspended users have their reputation reduced to 1 (and blocked to 1); as such, they cannot do anything that requires a higher reputation. Plus, since they are suspended, they cannot even ask or answer questions.