I bet this topic will receive many helpful tips. I’m a pair of brown shoes amongst tuxedos. I consider myself a newbie. I did experiment with a .22, and still have in my collection, a .22 revolver and .22 rifle.
.22’s are also not as loud in an emergency, but at the range - always wear ear & eye protection.
Rifles can be more accurate but slower to handle when one might be in a hurry. If they are semi automatic and can hold a lot of rounds, as many as your state allows for a .22 caliber, great.
I’ve heard that .22 semi auto (pistols) can be unreliable, and the best ammo can at times be harder to find and cost more, but I think still affordable due to the caliber and I think inventory. Semi autos can come in more higher capacity loads, again - check with your local laws too, to ensure you are within legal capacity limits for that caliber.
In your case, I wonder if a revolver might be a good start, but barrel length of 3 to 4 inches, for more accuracy, as you also have more of a gun to look down onto as you point. In the heat of such a moment, the mind might not easily focus on the front sight, I think.
I know the .22 has little to no recoil, but when I changed to a better grip, it was so much more comfortable and easier to shoot, especially since revolver triggers have a fairly heavy trigger pull.
For .22 caliber ammo, I prefer CCI brand, full copper bullet or at least copper plated. I did like the Federal Punch brand .22 ammo as my second choice. They seemed cleaner which is important to keeping the cylinder clean. Always clean the firearm after a day’s practice. For ammo, I prefer the “.22LR” (long rifle), which fits in most hand guns also.I do not prefer the .22 Long or the .22 short ammo. .22LR is common.
As others have shared in other posts, what’s also important is that the person, your housemates feel comfortable and they get to choose what they want, the type, model, and or caliber they like best; It can differ per individual. Then they can experiment, try out different ones and work their way up from there over time, and take their time. Best regards.
Already, you’re on fire. Have fun.