A gas turbine engine fuel nozzle assemblage (10) comprises a nozzle outer body (25) comprising a premixing section (23) and an interiorly disposed first fuel passageway (22) to supply fuel to the premixing section (23), and more interiorly a central channel (33) comprising an inlet (30) from an air supply, an aperture (19) at an upstream end to receive a lance (18), and a downstream-disposed annular bearing surface (21) adapted to slidingly engage the lance, the fuel nozzle assemblage adapted so that the lance may be alternatably selected as any interchangeable one of a gas lance, an oil lance, and a non-fueling dummy lance. Between the lance and the central channel (33) is formed a cooling fluid passageway (24) that is in fluid communication with the inlet (30) and one or more cooling fluid passageway exits (60). The interchangeability of the lances (18) is effective to provide a desired flexible functionality to said fuel nozzle assemblage. The architecture of the fuel nozzle assemblage (10) may be utilized for higher level architectures of benefit to gas turbine engine facilities.