Gate 1+2 screening of the CrB→MnB→FeB→CoB Pnma FeB-type monoboride family. ALIGNN-OSZICAR magnetic moment and Curie temperature predictions, with MnB calibrated against the Lambertazzi et al. 2025 experimental anchor (Tc=586K, Ms=15.5 Am²/kg). MnB and FeB pass both gates; CoB and CrB fail Gate 2.