I agree with your selection.
A good 12-gauge pump shotgun; a reliable semi-auto rifle; a reliable handgun with which you are proficient. I like wheel guns, as well; but if I had to be limited to one handgun, I’d go with a Glock 19 (one reason is that 9mm ammo is far more obtainable than .38 SPL or .357 magnum; another is the 15-round magazine as opposed to a five or six-round cylinder).
I can’t argue with your reasoning for the Glock 19 or any 9mm semi. But a handgun is for close up defensive work and that rarely requires more than 6 rounds. I love the reliability of a wheel gun. But I have to admit my EDC is a 9mm semi.