What is the ruling on one who apostatized after midnight, then recited the Shahada during its time, and should he pray 'Isha, knowing that he had not been praying out of laziness, then repented and adopted the view of those who do not obligate him to make up the prayers?

The time for the Isha prayer extends until the break of dawn, though for Hanbalis, after the first third or half of the night, it becomes a time of necessity. If an impediment to prayer is removed before dawn (such as a disbeliever embracing Islam or a menstruating woman becoming pure), then it becomes obligatory for them to perform both Isha and Maghrib prayers together, because the time for Isha extends to Maghrib in times of necessity. As for prayers missed due to laziness, it is preferable to make them up to avoid scholarly disagreement and to act upon the opinion of the majority.