Mysha, I like what you've done here--I think this is a nice interpretation. What you don't have is the scansion, the rhythmic pattern of my verse, which was created to fit a particular tune (and which also fits a very different tune--but fits them both because the accents fall in the right places. Here's how it fits Arlo's interpretation of Tom's tune:

Since our FIRST ancestor SLITHered from the OOZE
We've been ITCHing to try ON our dancing SHOES
From our FIRST step through the TWO-step
And the LOCK-step and the GOOSE-step
We've been WORKing out the STEPS to dance the BLUES

For the Limerick reading it fits as iambic with the first foot foot of each line anapest:

Since our FIRST anCEStor SLITHered FROM the OOZE
We've been ITCHing TO try ON our DANCing SHOES
From our FIRST step THROUGH the TWO-step
Through the LOCK-step AND the GOOSE-step
We've been WORKing OUT the STEPS to DANCE the BLUES

(that's forcing the scansion a bit in the limerick version--the third and fourth lines of a classic limerick are usually anapest dimeter: duh duh DAH duh duh DAH-- and the other lines often have a strong anapestic feeling, as well.

But anyway, if you try accenting them as I indicated, over a guitar rhythm, I think you'll come closer to the melodies.

Charles