Most people advocate a MVP approach (minimum viable product) for many reasons. First, you can do less work before releasing. Second, it allows your ideal users to help you develop the product further. The few users you have (heck even if it is only 5) will be able to tell you what they like, how it is useful etc. You may not know all the uses for your product and a group of people might find that it is useful for X. Then you can market it as the "perfect solution for X"
Your initial users will most likely be HN members. Most of us know how hard it is to do all of those things so we're not going to worry if you don't scale in a timely manner etc. If your site crashes, we'll calmly inform you, if you take a while to respond to feedback, we will understand.
I'll send you an email and I'll see if I can help you..