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I noticed your question had been online for a while but no one had picked up. The likely reason is that there isn't a place to get examples of entertainment law contract terms that are correct. I've seen a number of them over the years on the web but most of them were not just bad but were, in fact, not based on the law at all and I suspect were drawn up by non-lawyers.
As to your first question, you can do contracts that involve more than one party but it is generally not a good idea and there is no reason to do so. You should always use different contracts for each person you represent for a variety of reasons.
As to where to find terms, I'd suggest that you either hire a lawyer to draft the initial contract or use a form generation service like this one. There is an interesting article explaining why internet forms are a particularly bad idea for entertainment law at http://firemark.com/2013/07/05/why-its-dangerous-to-rely-on-free-online-entertainment-law-contract-forms/
Let me add one more reason to the ones set forth in that article. Typically, the only way you know that your contract has problems is when you get sued and lose. By that time you have spent tens of thousands of dollars in attorney's fees, if you lose you will likely have to pay the other side's attorney's fees and costs (tens of thousands more), plus you will then lose whatever amount of money you should make under the contract. It's different than using an online for something like a divorce where the judge just tells you to either redo the form or hire a lawyer.
The attorney who wrote the article linked to above may even be able to provide you with the contract you want, I know that he sells form "bundles" for various entertainment projects and he is pretty well known in that niche.