Just traded a Patriot for the Wrangler Unlimited and have driven quite a variety of cars in the past few years. I also have a 2 year old (and am expecting another soon), who rides with me on a daily basis.
1. The interior noise level with the hard top isn't too bad. Sure there is a little bit of wind noise, but at highway speed, it has similar noise to a fill size pickup (Silverado, F150, etc) and actually seems a little quieter to me than the Patriot I had. To me, it seems noticeably quieter compared to small, 2-door coupes (Civic, Scion tC, etc) just because the tires aren't as loud and you're not as close to the road. If you get bigger tires at some point, you should expect more tire noise.
You can also cut down the noise a little bit with one of the headliner kits (search the forum, there are a few threads). I haven't done that yet because the noise isn't bad enough to make me want to.
2. The trunk space is adequate. There is quite a bit more cargo space in the JKU than in the patriot and is probably similar to my wife's Malibu or any other full/midsize size sedan. Definitely less than a Tahoe/Expedition, but enough to carry a full stroller and good deal of groceries at the same time. I imagine it would be similar, if slightly smaller, than your wife's Cadillac.
3. The ride to me is fine. More in line with a full size pickup than a coupe, sedan, or crossover, but that is to be expected. Is it excessively bouncy or harsh? I don't think so; you'll feel potholes and bumps in the road, but its not going to throw you or your passengers out of their seats. The roads around here aren't exactly great, and big potholes don't feel great, but its not substantially worse in a Patriot than any other vehicle I have driven recently.
My 2 year old actually loves going over bumps in the Wrangler and says "more please" every time we hit a decent one that lifts you up a little bit, which he never did in the Patriot or my wife's car.
If you go into the JKU expecting it to be a little noisier and a little bumpier, you'll be fine. It won't ride as nicely as your wife's Cadillac, will be a little louder, and won't have as many of the creature comforts, so if you're okay with that then you'll love the Jeep. On the other hand, if you expect it to be like an SRX, Grand Cherokee, Acadia, etc then you may be disappointed.
In my opinion, that's part of the fun of a Wrangler - its not as refined as some cars on the road, but its a hell of a lot more fun.