1. If the gazzet by the state government restricting the gathering of a certain number of people is active, any political gathering without seeking the state government consent is null and void, even if such gathering was successful and uninterrupted by the government.

2. If APC goes ahead with their proposed primaries and subsequently partakes in the governorship election, and APC is declared winner, such winning can be challenged in Court. As the primary was conducted without respect for the established authority of the State

3. The second runner up would be declared winner on the grounds of technicality.

How do you think things will play out?

Executive order is not a law. It is just an administrative directive.
OP please quote the section of the constitution that backs the so called Gazzette.