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 (4πM <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">s</inf> ) and the uniaxial anisotropy constant (K <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">u</inf> ) in laser-annealed, substituted EuYIG films from approximately 50K to each sample's Curie temperature (T <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</inf> ). In films (with identical composition) whose room temperature magnetizations vary by nearly 2:1, we find thermal dependencies for 4πM <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">s</inf> that support the simple cation exchange model for laser annealing. The temperature dependence of K <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">u</inf> is remarkably linear from 100K (below saturation of 4πM <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">s</inf> ) to about 50° below T <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</inf> in each sample, indicating a significant magnetostrictive contribution. Temperature stabilities of 4πM <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">s</inf> and Q are also discussed.