I am certain there`s no issue here. That also goes for the "whip it good" and costume design part. It would be too hard to prove the success of the shop was due to the `parody` of the music industry.
As for
CraigL comment about 16 bars... that`s only part true. It all comes down to proving the
success of the second song using the 16 bars is strictly due to the 16 bars usage or if there are other elements taking place which provides the success.
For example, if my hit tune uses 16 bars of a previously created `super hit` and reaches fame itself, then the original artist could take me to court for copyright infringement. That doesn`t mean they will win. While in court they would have to prove that the only reason my song was successful was because of the 16 bars I used from their song. That would be very hard to prove, but no one wants to go through that... So once you reach that level of `income` or attention, it`s much easier to settle out of court and give the original artist a cut. Then everyone`s happy. After all, the lawsuit likely didn`t start because one artist was mad at another for using it. It typically comes down to getting paid.
(It`s been a little while, but I did take a couple of copyright law classes, but that makes me no expert. I am not a lawyer, and laws do change... but during class, this is one of the issues we concentrated on because Rap music was doing exactly this...)
All in all, I don`t think you`re going to have any trouble... and hey... if you do, think of the press release you could write about the situation. This would get you so much additional attention, that you might be happy to `share` a little of the income with a lawyer. After all, they won`t take it all... they just want a little.

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Vincent Wilcox (a.k.a. KRAKR)
Drummer
My band:
Letters Make Words