1) In order to apply for citizenship, one needs to show Good Moral Character as a requirement of the application, and this has to be for the last 5 years. As such, someone in your situation would have to wait to apply 5 years after parole ends. This is when the time begins ticking for the year requirement. So you could file, but not just yet.
2) There is a risk. Although ICE deemed you not deportable at the time, they can always change their mind. This is unlikely since USCIS/ICE/CBP focuses more on (1) recent arrivals, (2) aliens with threats to security and (3) aliens with serious criminal history. However, while I do not know what you were specifically convicted for, it may fall under one of the issues listed HERE. If so, USCIS/ICE can decide to trigger removal. Thus, one wants to be SURE that the conviction does not fall under one of those issues before applying 5 years from the time the parole ends.
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