FounderDating.com is a great place to start because they do some vetting. Forgive me for assuming, but it sounds like you have an idea, and need someone else to build it. If I were that developer, the baseline would be 50/50 and I would want to know that you were going to work as hard as I do. Be aware that as soon as you have revenue, bring on other founders on an equity only basis gets harder, not easier. So pick this person(s) wisely. In most cases, their goodwill is all you have to get you funded.

Start ups need fewer things to worry about. Follow the KISS principal and file in the state where you reside unless you have a rock solid reason not to. If nothing else, you will easily find a layer licensed in your state. You can always do an acquisition later to grow into a larger entity.