We present a simultaneous analysis of galaxy cluster scaling relations between weak-lensing mass and multiple cluster observables, across a wide range of wavelengths, that probe both gas and stellar content. Our new hierarchical Bayesian model simultaneously considers the selection variable alongside all other observables in order to explicitly model intrinsic property covariance and account for selection effects. We apply this method to a sample of 41 clusters at 0.15 < z < 0.30, with a well-defined selection criteria based on RASS X-ray luminosity, and observations from Chandra/XMM, SZA, Planck, UKIRT, SDSS, and Subaru. These clusters have well-constrained weak-lensing mass measurements based on Subaru/Suprime-Cam observations, whic...