even if sound, the argument does not suggest anything "divine", sentient, conscious, thinking, caring, loving, warranting worship or prayer, so this amounts to unwarranted or ad hocpersonification/anthropomorphization; rather, Craig's conclusion shadows Aquinas' definition inSumma Theologiae, which hence smuggled his God in the backdoor with the baggage
No, it's not smuggled - it's basically argued for. The reason why it's a God instead of any other being is i) the being must be simple. Which means it cannot be material as that would be composed of an aggregate of parts that would be conditioned by those parts. As generally parts are contingent entities. ii) The being must be immutable, or else it's conditioned by change. iii) It's unextended, immaterial, and eternal, then since it cannot be conditioned by space and time. It would also have to be omnipotent otherwise it would be conditioned by its limitations. iv) It then follows if it's omnipotent, it's also v) omniscient and vi) omnibenevolent.
if there was a definite earliest time (or "time zero"), then anything that existed at that time, began to exist at that time, and that includes any first causes, gods/God, or whatever else
The first cause doesn't have to be temporal. It's an instantaneous cause.
an "atemporal", "eternal" cause of a universe that has a definite age (like 14 billion years) is incompatible with the principle of sufficient reason, since such a cause leads us to expect an infinite age of the universe - there's no sufficient reason the universe is 14 billion years old and not some other age (yet item 1 is supposedly related to sufficient reason)
God isn't in time as a duration, or an extension of the universe. He's a pure act. The universe being any age is completely compatible with this, and it holds with the PSR since the PSR states all things have to be given a reason for.
spacetime is an aspect of the universe, but "before time" is incoherent; causality is temporal, but "a cause of causation" is incoherent
Nobody in classic theism denies this, though. That's why the first cause isn't temporal.
Also, I'm not sure of it's very absurdity. Even the transcendentalist would argue for a condition of possibility for causality to exist at all - though as a concept of pure understanding.