Laser annealing makes available substituted bubble garnet films with identical composition but widely differing cation distributions. To investigate the thermal dependence of the magnetic properties of these films, we developed a high temperature bubble statics technique (293 to 440K), and employed variable temperature SQUID magnetometry (4.3 to 400K) and ferromagnetic resonance (∼7.5 to 293K). We have studied the variation of saturation magnetization (4πMs) and the uniaxial anisotropy constant (Ku) in laser-annealed, substituted EuYIG films from approximately 50K to each sample's Curie temperature (Tc). In films (with identical composition) whose room temperature magnetizations vary by nearly 2:1, we find thermal dependencies for 4πMsthat support the simple cation exchange model for laser annealing. The temperature dependence of Kuis remarkably linear from 100K (below saturation of 4πMs) to about 50° below Tcin each sample, indicating a significant magnetostrictive contribution. Temperature stabilities of 4πMsand Q are also discussed.