I've had my own doubts about Release Date Change being distinct enought to qualify as a separate trope, but...
As I've long understood the term -- which I first heard years before TVT was founded -- Development Hell is (or at least was) the pre-production and even pre-pre-production stage of film-making, where the creative team (or the studio) is attempting to whip a project into shape and promote it to management so that it will be greenlighted and become a genuine work-in-progress. EDIT: It's when this period extends past a reasonable amount -- more than a year or so, or when the project is abandoned -- that the project is said to have entered Development Hell.
Schedule Slip is for a work that appears in installments, ostensibly on a regular schedule. The work already exists -- it's just that the creator misses an installment, and the interval between the installments slowly grows.
Vaporware is "we've got this great program, it'll be coming out real soon now" but the program doesn't actually exist and may never exist. There is (or was, at least originally) an element of deliberate deception in vaporware, as it was usually employed to take the wind out of the sails of a competitor with an innovative new product by claiming your version of the same kind of product was just weeks or months away from release, thereby convincing customers to wait for your version rather than give money to your competitor right now.
Release Date Change is simply "the date it was to come out changed". Which could be any and all of these.