I started practicing immigration law last year and I have been envisioning a platform almost exactly like this recently. Particularly your eligibility test -- you nailed it. I think this is a good value proposition for people who want to DIY their petitions.
What is your marketing strategy? Adwords may be tough because you will pay $4 per click, competing with lawyers who earn $2,000+ per conversion while you'll get $99.
Are you looking for only big investors? I can't invest much but would be interested in getting involved in some way.