(Re. #2) Because of Clojure's immutability, you program differently than you would in a state-based language (most mainstream languages). So learning Clojure is not that helpful in preparing you for Common Lisp or Scheme. Just learn Common Lisp or Scheme, if that's your final goal.
(Re. #3) I've seen web pages detailing jobs in Common Lisp. Search, and you'll find them. Short answer: I don't think there are that many. Some independent programmers who have (or take) the liberty of using whatever language they want, get to use Lisps that way.
Re. "I'm not too deep into Java" and similar statements: FYI, Clojure is built on top of Java and depends on Java being used to get things done. Clojure doesn't implement various things because of this; the language assumes that you know Java well enough to "drop into" Java when Clojure itself doesn't provide. (Clojure makes it very easy to do this, most but not all of the time--and the exceptions aren't documented.)