It certainly makes sense to "stay in touch with potential customers and clients all the way through the process" and to brainstorm ideas with former colleagues and friends. (Groups like HN can help too)
However, I don't see any of this as being unique to a single-person startup. All of this is also true for startups that aren't "single-person startups".
As for "Twelve days into my project I had to scrap virtually every piece of code I had written - everything. It was a disaster." throwing out code isn't unique to single-person startups. Larger startups and large companies can tell you that they've thrown away much bigger efforts :)
However, I don't see any of this as being unique to a single-person startup. All of this is also true for startups that aren't "single-person startups".
As for "Twelve days into my project I had to scrap virtually every piece of code I had written - everything. It was a disaster." throwing out code isn't unique to single-person startups. Larger startups and large companies can tell you that they've thrown away much bigger efforts :)