There are a couple of issues to consider here...

First of all, whether you own the copyright in the film or not depends on what your contract of employment says about "inventions and works of art". In most standard employment contracts (here in the UK at any rate), there will be a clause saying something along the lines of "if you use company resources to develop your idea/work/invention, then the company owns the copyright." Your best bet here would be to take a look at the terms of your contract, and if necessary, clarify the company's position with your manager.

On the music issue, you will also need to get each of the bands to not only sign a release for each member appearing in the film, but you should also get them to sign another release to use their music. These should be done as seperate releases, and you should be very careful to ensure that the bands allow you to use the music in all media, in all territories, and in perpetuity. Ideally, you want the music agreement to also be royalty free (so you don't have to pay the bands anything). If they do want to be paid, then you'd probably better get a lawyer to draft an agreement up for you.

Ben.

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filmmaking.net
(Incorporating the Internet Filmmaker's FAQ)

Please note the opinions expressed here are those of the author only and do not constitute legal advice. The author cannot accept and liability whatsoever for inaccurate or outdated information contained within.
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