I know you asked for recomendations for pump guns, but I bought my son a beretta 391 youth model auto. I set it up to hold one shell at first. You can add to the stock as grandson grows and have a great gun with less recoil that will last him his entire life.
I hunted with a friend's Beretta and i used 7.5 shot. I just learned that the shot pattern of the 28 guage is far superior to that of the 410, so I sold my 410.
I think the best gun for home defense is a good plan that everyone in the home knows and knows what to do. I also think shotguns are the best weapon to use in the home. It does not have to be 12 gauge 20 is fine