I was always taught that it's third person omniscient, though I suppose omniscient always has to be third person, so why not just say omniscient POV? When I wrote third omniscient I just meant omniscient.
As always, glad to receive your input, Bufty!!!
Me too. I was taught that third person is when "I" is not telling the story, where all characters are referred to by their proper names or he/she/they etc., regardless of whether it's limited, objective, or omniscient.
Omniscient is when the narrator knows all, regardless of whether it is third or first person (first person omniscient is rare, but it can be done:
Galapagos,
The Book Thief, and
The Lovely Bones are examples of this).
As for the "as if" versus "like" thing, technically like is a preposition, and as is a conjunction. But people have been using like as if it were a conjunction for quite some time.
She stared at him, as if he'd grown a second head.
She stared at him, like he'd grown a second head.
Technically, you're only supposed to use like when no verb follows.
He swam like a dolphin in the water.
But whether or not it's strictly grammatical, most people talk this way. To me, it's a matter of whether or not your use of like instead of as fits the narrative voice you're using. It certainly should be considered for first or limited third, but sometimes omni narrators are less formal too.
I'm sure one's editor will weigh in on whether they think it fits or not too.