The wife is comfortable with the 10/22, per the OP. I own several, and all of them are quite reliable. No recoil, easy ammo availability, reliable high-capacity magazines, and they don't rely on manual operation for follow up shots. The ammunition is also cheaper, so one can afford to practice, again, without recoil.
The .410 can, in five rounds, hold 25 projectiles, but you're launching them with less precision, five at a time. You get five pulls of the trigger, one fifth of the total of a 10/22 with a BX25 mag, against a moving target.
There's also the matter of recoil, and noise.
The Rossi also has it's own reliability issues. Some shotgun shells crimped petals are longer than others. If the petals open into the forcing cone on firing, it locks the gun up.
Remember, the OP stated that his wife is recoil shy, and has NO interest in a handgun. That limits her ability markedly. To me, get her the 10/22. If she likes to shoot, curiosity will inevitably lead her to try other guns. THEN, you can get her into more conventional firearms.
In the end, there are no degrees of death. A person dead of a .22 caliber rounds is not going to be less dead than one dead from a .50 BMG. As most encounters still happen at less than 7 feet, in low light, against an unarmored foe, and in a frontal shot situation, it really doesn't take a lot to stop the fight.
