I think your book could be a good tool. I would emphasize the need to create realistic, multi-year pro forma financials for at least the next three years, with at least the first twelve months broken out. It is way too easy to underestimate the funds needed for start-up and overestimate profit in the first few years. Everything needs to be accounted for, and some, as there is always something else that needs to be purchased or invested in. Plus, make sure to account for ongoing investment in the business. I would think it would be very useful if you showed in detail how to create financial projections, as a lot of people don't know how to do that part of a business plan.
I agree with a lot of what has been said. I will add one thing from my own experience. Do assume it will take you longer to be successful than you think. I have started two different types of businesses now, and I can tell you that the learning curve is a big factor. This is especially true if you are a sole proprietor or single operator with no staff. It will take a long time to get your business up and running, and performing well, so plan ahead for a realistic time line to achieve your goals.
Lots of good comments so far. I would just add that you should 1) get a referral from a trusted source if possible, 2) try to get more than one referral so you can get at least 3 proposals to compare service and costs 3) go out and research SEO as a concept so you can make an informed decision. There are a lot of scams or simply ineffective companies out there, and bad SEO can actually hurt your brand online, because Google can blackball your site from search results if you do something against their policies. Take your time and do your diligence!
For a website, I would estimate the traffic you expect to see from each channel, and then assume you convert 2 to 5% into sales. From there, estimate the average $ sale per conversion, and you have your revenue model Although, you might start with a low conversion rate and assume it grows over time.
LinkedIn is a great resource as many people have recommendations on their profiles. Have you spread the word in your networks so you can solicit referrals? What about networking in person, in your industry, or wherever you might find that skill set, to meet new people? I think nothing compares to interacting with someone in person. Then you will have to trust your instincts. Also, make sure you speak to a business attorney about all the possibilities if you "break up."