How do you handle copyright and profit sharing for an ebook anthology?

The good news is you don't need a lawyer. The bad news is your contract will only be as binding as the jerkiest one of you allows. Okay, let's start with contracts. Contracts are agreements. There may be boilerplate contracts out there that are customizable, I'd definitely just go ahead and search engine it. "Multi-author " or "partnership" contracts. The thing about agreements are, if one or more of you start to hate each other midway through the process, the agreement will barely be worth the paper its printed on. And if that happens, I guarantee lawyers will be involved. Contracts should include things like how profit and loss will be decided and how it will be split. I cannot tell you if there is a standard...my experience is that each publishing house has its own standards and if you are self-publishing, profit is unlikely to be an issue.  I'd suggest you define profit as what is left over from gross incoming sales, after publishing costs, shipping costs, marketing costs are taken out. (You won't be skimming from the profits for printing...that money goes up front. You pay for production before you see a penny in sales.) If you want to split profits evenly, you will want to define what profits are, who determines them, how they are reported to the others, at what interval, and which outside auditor will oversee the reporting when you no longer trust one another. Copyright is as simple as stating that each author has full and complete rights to their own content, with republishing and reproduction rights. Again, this is the very least of your concerns. Even without this, an author is presumed to own their content, unless otherwise stated. I.e., if you wanted no one to have rights to their content unless the other two agreed, you'd have to say that. Now let's step back for a second. Self-publishing can be a positive experience. If each of you brings an interested audience with them, you have 3x audience you can market to without much effort. If more than one of you is not particularly well-known, you need to be able to get the word out. Do you have a marketing plan? How are you going to tell people about the book? What is each one of you responsible for in terms of marketing? Wait, step back even further. Do you have a professional editor? Cover art? Someone to oversee production and shipping? How about fulfillment? Book publishing is still a process and of every single thing in the process you need to think about, "profit" is last on the list.

It may be possible to do the contract without an IP attorney, but it wouldn't be smart to do so. Each writer already HAS copyright in his or her chapter, and is licensing some or all of the rights to you by contract. You probably should have each writer register his or her own copyright separately (and provide proof of registration to you). You want a non-exclusive license for all current or future formats of the anthology, with a term to continue until X happens (I would suggest either a fixed time, or until all sales drop below $x  per y length of time). There are a lot of other clauses you want to include. At very least, you need a good book on contracts for the book publishing business. There are quite a few. Get one from your favorite retailer or library before you go one step further.