Aren’t the two meters your friends are proposing the same thing?
An iamb and three anapests: u / | u u / | u u / | u u /
Three amphibrachs and an iamb: u / u | u / u | u / u | u /
Without the |foot| markers, they’re exactly the same: u / u u / u u / u u /
And foot divisions are kind of artificial, right? I’m not an expert; if there’s some nuance that I’m missing please someone call me out on it.
If you're interested, while I was trying to work this out, I went through your poem and annotated most of the first stanza in excruciating detail with analysis and concrit. I'm having some problem with HTML where the stress marks aren't lining up over the syllables I want them to line up with. . .let me know if you're curious about what I'm driving at but can't figure it out.
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Summary impressions: The meter is fun and bouncy (appropriate for a jokey Facebook-status poem). There are few variants, and those which are present feel unintentional rather than like deliberate storytelling strategies. I find long series of rhymed couplets irritating, but am forced to admit that their jingling, cutesy tone is appropriate for a silly poem celebrating a holiday with a pun baked into the date.
/ /u u / u u / u u /
Wise Obi-Wan, grey-haired and weathered by age
(Spondee, anapest, anapest anapest. I see how some of your friends may have decided that first foot was iambic, but I wouldn't do that myself -- as an actor, I would stress it to avoid its getting lost and the audience's thinking of Obi-Wan as merely a doddering old man. Plus starting on a spondee is usually pretty strong and dramatic. I like it.)
OR
(Antibaccius, two amphibrachs, and an iamb. If the first syllable is unstressed (as I advised against above), you'd get three amphibrachs before the iamb.)
u / u u / u u / u u /
Had long been in exile from Emperor's rage
(there's the initial iamb and series of anapests your friends were talking about, or three amphibrachs with an iamb on the end)
u / u u / u u / u u /
Until Princess Leia in desperate appeal
(Just like the last line. I feel like "desperate" has too few syllables and want to spell it "desp'rate," but I think that's just my problem :P)
u / u u / u u u / u u /
Did Artoo and Threep'yo into peril most real
(What is that one extra unstressed syllable doing in the middle of the line? In neither of the proposed meters should there be three unstressed syllables in a row, and I don't think this moment in the story is dramatic enough to justify breaking the meter this way -- it causes the reader to halt and stumble for a moment, which is good if you want them to dwell on a line or phrase, but here just gets in the way of understanding this important bit of exposition. I suggest rejiggering this sentence (perhaps try replacing R2D2 and C3PO's names with something like "the droids," or using their full names, or their names in a different order). If you do decide to revise this, I also advise experimenting with ending this line on an unstressed syllable to help it flow into the next line, which is a continuation of the same idea. Putting a stressed syllable here, especially with the completion of a rhyme, makes it feel very final, which is confusing since that's not actually where the thought ends at all.)
/ / u u / u u / u u /
Send unto Kenobi to beg for his help
(Like the first line, with the same caveat about the first syllable -- I'd stress it, because the fact that the droids were sent is important information, but I suppose you don't have to.)
u / u u / u / / u u /
In helping their owner: bold Anakin's whelp;
(I'm torn over whether or not to stress "bold" -- obviously, having it unstressed fits the meter better (however one chooses to describe said meter, there's definitely a general pattern), but. . . it doesn't sound good to me. This poem is so much of a bare-bones summary that each rare adjective seems important. Also, I don’t think a semicolon belongs here, although Djel help me if I know what punctuation you should use.)
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This is approximately when I realized I ought to be doing my homework instead of nit-picking at a Star Wars poem that was probably written as a joke in less than an hour. Thank you for posting this; this is some of the most fun I've had procrastinating in a while!
--Key