What does a Securities and Exchange Commission do, and what technology services/solutions does it need to operate?

It stands for allowing someone to continue doing or use something that is normally no longer permitted (due to changing regulations, internal rules etc.)

Pricing for different tasks that require the same amount of time from you tells the Customer (and your subconscious) that you're working at a 5 on task x, but working at a 9 on task y simply because it costs/earns more. That seems to be a disconnect. Your time is your most precious asset, and I would charge for it whatever you're doing. If you build a site, and they are happy with your dev fee, but feel like you should charge less for SEO, simply let them find another SEO guy. That's their choice, but YOU are worth $xx.xx, no matter what you're doing. Also, in general, take whatever you're charging and add 10% to it. If you're still busy, add another 10%. Let the demand level determine how much work you do, and at what cost.

I'm not an immigration attorney, but I have made trips to Canada to find clients, and this is my understanding of the laws. If you are a Canadian citizen or permanent resident, you do not need a visa to come to the United States as long as you will not actually be working and receiving payment from U.S. businesses or employers while in the U.S. For example, you can visit the U.S. to attend trade shows, meetings, conferences, etc. without a visa. Here's a publication from the U.S. State Department that may help: http://travel.state.gov/content/dam/visas/BusinessVisa%20Purpose%20Listings%20March%202014%20flier.pdf

Because of the nature of your consulting business (web development) you have the advantage of being able to effectively offer your services remotely. I think more important than deciding between a large or small city, is finding a city where you would enjoy living and building a network. Is there a city where you have a critical mass of friends, family, potential business partners? Is there a city you'd simply be happier in because it fits your lifestyle, whether it's access to outdoors or city living? Do you have a more specific market segment you'd like as your clients? Do you want to service just tech startups? Health tech startups? Larger companies? Unless you plan to really narrow down into a specific niche, like consulting just for the aerospace industry where the companies are usually found in a specific city or region, web development offers you a lot of geographic flexibility. More and more companies like Automatic or Zapier have completely remote teams and the trend towards that is only accelerating. Choose a city where you'll be happiest and most likely to be able to participate in the lifestyle the city provides. Not only will you be more productive if you're happy, you'll have more opportunities to grow your network organically by meeting friends through your hobbies or social activities that then turn into clients. I'd caution against being overly analytical or coldly rational when making this decision. Follow your gut. Choose a city you'd love to live in and grow a business in. I know wildly wealthy and successful entrepreneurs in cities both small and large.

If you're using source control, it's easy to track source and control access — or revoke access — if someone leaves the company. Also, your developers should have signed a contract about the project itself that clearly places the source code under your/the client's/the company's control, and if/when they leave, they release all rights to code created under that contract. You can never be 100% sure, but these small steps will at least ensure a legal high ground should anyone steal code. Good luck!