Late to the party re the trigger- OEM is the way to go. 5.5 lbs TRS with a OEM "minus" connector. Dry fire and live fire. Some "sets" feel better than others. I heard a rumor that Team Glock would mix and match components until they had GTG extra sets, the would bag those sets together and swap them out wholesale as needed. FWIW.
Re the mag release: I have had excellent results with reducing, texturing and contouring a factory extended release.