Accurate prediction of soil properties is critical for sustainable land management and agriculture. Soil pedotransfer functions (PTFs) estimate difficult-to-measure properties from easier measurements. With the emergence of remote sensing (RS), such data are increasingly used to enhance soil databases, raising the question of whether integrating RS data with conventional soil measurements improves PTF accuracy. These effects must be evaluated alongside other influential factors, particularly model and feature selection strategies, yet their relative importance remains unclear. This study evaluated the effects of model choice, feature selection, and RS-derived data integration on predictive accuracy for four key soil properties: total nitrogen (N), available phosphorus (P), exchangeable potassium (K), and organic carbon (OC). A Bayesian hierarchical framework quantified the relative importance of these factors. Model selection had the greatest impact on root mean square error (RMSE) reduction: Ensemble reduced RMSE by -25.3% for N, -32.2% for P, and -28.0% for K, while Random Forest (RF) achieved the largest improvement for OC (-49.8%). Feature selection also reduced error, particularly for OC, where Forward Recursive Feature Selection (FRFS) and Recursive Feature Elimination (RFE) reduced RMSE by -38.8% and -39.0%, respectively, while Boruta increased RMSE by 15.0%. Remote sensing-derived data provided smaller benefits, improving RMSE by -4.8% for OC, -3.4% for N, and -2.1% for P, with negligible effect for K (0.5%). Permutation tests confirmed these RS-related improvements were distinguishable from random associations. Overall, model selection and, to a lesser extent, feature selection substantially enhanced PTF performance, whereas RS integration yielded modest, variable improvements.