I'd suggest a recumbent tadpole trike for your wife-- that's the most stable configuration (an extra wheel adds little but weight, rolling resistance, and cost), and being low to the ground, if she does somehow manage to crash it's less likely to cause injury. These are more common than you'd think, with a number of manufacturers in North America and more in Europe. You will have to invest over a thousand dollars, though.
For you and your daughter, I'd suggest starting her as a stoker on a tandem bicycle-- the stoker pedals, and breaks, but her reaction time won't put you in danger; the driver's breaks are the important ones. Unfortunately, she'd not be able to steer with you, but it's a good first step, and used tandems can be found relatively cheap if you're lucky. There have been tandems made with linked steering for the stoker, but I've never seen one; you might be able to convert one or find someone to do so.
Not as fun and social as a quadracycle, I suppose, but much more practical and for the price of one of those the you could buy yourself a decent commuter bike, a recumbent for your wife and a tandem for you and your daughter and still have enough left over to do it all again a couple times over if you forget to lock up.