Dektol is pretty much the "Old Standard", universal, all-purpose, ect. Don't know anything about Lauder chemicals.

Using both Dektol and Selectol-Soft is a common technique. It can be done by combining the two in some proportion to each other in the same tray, or by using them in separate trays. When used seperately, the paper is typically started in the Selectol tray until the highlight detail is developed, then shifted over to the Dektol tray to complete development.

Bottom line: Start with any of the regular standard developers. Once you start gaining some experience, then start getting sophisticated by trying other developers/combinations/dilutions.