Chiefyman, I have the same situation at home as you mentioned. I've been an active shooter for many years, but my wife and her mother are not shooters. They are interested in having protection but they aren't interested in doing much in the skill building department beyond familiarization.
For people such as these the weapon needs to be one wherein they need do nothing more that identify the target, point the gun, and pull the trigger.
Caliber should be no greater than .38 spec. or 9mm. I don't want them to be in a state of semi-shock from the noise, muzzle blast, and recoil so that they can not fire a second or third shot if need be. A weapon fired inside a room multiplies all of those distractions by three. (non-scientific)
Finally the weapon should be easy for them to shoot. It should fit nicely in their hands. It should point naturally.
I selected S&W K frame revolvers. I have a model 10, three model 15's, and a Colt Police Positive (all are .38 spec., and all have 4" barrels.) that are each stashed in a different part of the house so that wherever they are, the women have instant access to a gun.
Personally, I think the smaller J frame .38/357 revolvers are a little too difficult for a novice to shoot well. I like the J's, and I have several. But my wife couldn't hit a five gallon can at ten yards with a J frame, yet she had no trouble hitting with the K frame guns.
A double action only semi-auto would probably serve just as well, but they tend to be more expensive. Besides, I already had the revolvers.