Q 1: Why is the term "quest" used here?

A: The process for studying the historical Jesus is called "quest" because Albert Schweitzer called it that in 1906, and it became common thereafter. If Schweitzer had called his book "search for Jesus" that may have become the topic name. But the whole field now calls it "quest", in the same way that New York is called New York. The fact that scholars widely use the terms "second quest" and "third quest" is an indication that the term has been totally attached to the topic now, and is hence used per WP:Commonname.

Q 2: How is this article different from Historical Jesus?

A: This article discusses the "processes and the techniques" used by academics. The Historical Jesus article discusses the end product of those efforts. This is in the same sense that automobile manufacturing is the process by which automobile is produced as an end product. Another analogy for this article being about the "academic process" and the Historical Jesus article being about the "material/end product" is this:

  • The article Coffeemaker discusses a "device and a process" for making coffee.
  • The article on Coffee discusses material involved in and produced by the process.

Of course, the Coffee and Coffeemaker pages refer to each other, but they are separate concepts and separate articles. So this article (which is about the process) and the Historical Jesus article (which is about the material/product) refer to each other, but are distinct concepts and articles.

Q 3: How does this article fit in the overall scheme of the articles on Jesus?

This article is about "techniques and processes" for gaining an understanding of Jesus. The article Historicity of Jesus on the other hand does no address these issues, but only focuses on the very basic issue of the "existence of Jesus" - in effect only addressing the question: "Did Jesus walk the streets of Jerusalem?". The Historical Jesus article discusses the various aspects of what can be understood about the activities of Jesus as he walked the streets or preached, e.g. "Was Jesus seen as a social reformer by the people of his time?" These are hence three different aspects and topics with three separate articles. For a further overview of the related articles, please see Jesus and history which lists more items.