Pre-consolidation alters the interfacial state of prepreg laminates and can influence inter-ply friction and downstream forming behavior. This study characterizes the dependence of inter-ply friction on pre-consolidation in an aerospace-grade unidirectional carbon fiber–epoxy prepreg (AS4/8552) across representative temperatures, sliding speeds, fiber orientations, and consolidation dwell times. Increasing pre-consolidation substantially raises both the critical and stable coefficients of friction, with the strongest effect observed for the critical coefficient at elevated temperatures (65–85 °C). While changes in stable friction are consistent with a mixed-friction framework in which consolidation drives interfacial evolution. The critical coefficient exhibits a stronger dependence on pre-consolidation, consistent with the progressive development of an additional inter-ply interfacial shear resistance during dwell; this contribution is quantified through a joint shear force parameter introduced in the present work. A fixed-noise Gaussian Process emulator was then developed to represent friction continuously across the tested processing window, with uncertainty taken directly from the GP posterior. Coupling the emulator to a validated analytical forming model yields a sensitivity analysis in which propagated friction uncertainty shifts the formability indicator, with temperature, sliding speed, and dwell time acting as coupled process variables. The combined experimental, probabilistic, and analytical framework offers an uncertainty-aware route to ranking forming conditions during preliminary process design and to informing process optimization in composite manufacturing.