Skip the pistol grip, that shit is stupid. Get a Remington 870 in any configuration so long as it has an 18" barrel. Then, regardless if you get a 12 gauge or 20 gauge, get this stock:
http://www.blackhawk.com/product/SpecOps-Adjustable-Shotgun-Stock,1158,1447.htm
That way the wife won't mind shooting it because it won't hurt.
As for a handgun, get a fullsize no matter what brand you go with. My girlfriend prefers my 1911 over top of my 9mm Springer XD subcompact. So go to a range and use the rentals to see what you like. I suggest any 1911 in .45, as for 9mm try out the Smith & Wesson M&P, Springfield XD Tactical and XDm, Glock whatever (I'm not a fan of them but they are dependable, just stay away from their .40 cals), Sig Saur, maybe a Walther.
It was said before, but for the shotgun set up some hooks up high so the kids can't reach it, but more than that teach them safety, and make sure they know that if they touch it they will regret it. For the handgun, there are small safes out there that have buttons for each of your fingers, so you press a sequence and it pops open.