por-cue-pine
The “k” sound is definitely the beginning of the second syllable and not the end of the first.
Option 1, but I think I’ll begin pronouncing it ‘Pore-shoe-peen’. Because it sounds fancy and vaguely ‘European’ (see ‘Jag-you-are’ and "al-you-min-i-um’).
I don’t think he originated it, but was reflecting a southern dialect (although Kelly coined quite a few words and phrases in that genre).
My mother, who didn’t have the slightest idea who Walt Kelly was, nor would be likely to read any comics (the work of the Devil, they were), used the term “porky” informally, much in the same way she used “possum” or “wood pussy” (for skunk). And all her life she wondered why people laughed when she said she saw a skunk that way; she never caught on.
Porkwarbler Mangrupine.
Pour Cue Pine
por-cue-pine:D
“Pork-uh-pine,” but only for the same reason that I pronounce another word “speck-tack-uh-lar.” Not sure what that reason is, but it’s what I do.
I used to say porkypine, but I say porc-you-pine now.
Closest to the top one, but the second syllable is neutralized, closer to a schwa. Closer to a dropped off “ya” at the end of a sentence than a “you.”
How often do you use porcupine in conversations ? 
I chose option 1, though I divide the syllables slightly differently than you: porecuepine.