There cannot be two "First" resurrection events. According to II Cor. 15:23, in consecutive order, those would be the first resurrection of Christ and the Matthew 27 saints raised by Him in AD 33, and "afterward" the second resurrection that took place at His coming. You know, the resurrection that Paul told Felix, Timothy, and those on Mars Hill was "about to" take place.
"And have hope toward God, which they themselves also allow, that there is about to be a resurrection of the dead, both of the just and unjust...And as he reasoned of righteousness, temperance, and judgement about to come, Felix trembled, and answered, Go thy way for this time; when I have a convenient season, I will call for thee." (Acts 24:15,25).
"I charge thee therefore before God, and the Lord Jesus Christ, who is about to judge the quick and the dead at his appearing and his kingdom;" (II Timothy 4:1).
"And the times of this ignorance God winked at; but now commandeth all men every where to repent: Because he hath appointed a day, in the which he is about to judge the world in righteousness by that man whom he hath ordained; whereof he hath given assurance unto all men, in that he hath raised him from the dead." (Acts 17:30-31).
All three of these texts refer to the second resurrection event that was soon going to take place in that first-century generation.