I should add that I'm talking about undercounter appliances in both cases. The only combo full size units I've seen (which we could put in the butler's pantry / wet bar) are very expensive. Thx!

I'm starting to do my research and it seems like the $700 fridge has good reviews, but some people were posting about the noise. We are usually watching tv or cooking and I didn't think a little noise would be a problem.

We had a cabinet built in specifically for the wine cooler on one side and the TV accessories on the other. The stained butcher block cabinet top stretches across both sides, but the wine cooler door is THE door on it's side. The cabinet door hides the TV stuff on the other. Looks great. I see no reason why you can't do the same with an existing cabinet. Just took this photo of mine so you can see how we did it. Wine cooler is on the left as you look at it. We use the top for booze, and built in a cabinet for glassware on top of that. Sorry it's sideways. I straightened it in photoshop, but the web still flips it. You get the idea anyway hopefully.

The IT person in me says this is a security problem, so you need to first identify your threat model. In a best case scenario, you can trust your kids and you teach them to treat alcohol with the appropriate respect; but you also avoid any taboo around it. This probably involves going ahead with a good example (i.e. drink responsibly and don't get drunk) and also letting them taste from your drinks when you have some. If you generally think you can trust them, but you are not 100% certain, then maybe all you need is an alarm system that tells you when it was tripped. Sticking a magnetic sensor onto the door and hooking it up to some sort of alarm system would achieve this goal. There are plenty of different ways of doing this. A quick search finds: https://smile.amazon.com/dp/B085HTMGYV combined with https://smile.amazon.com/dp/B07TQLKQLJ. I have not used this product before, but I think it could be set up to send you a text message whenever somebody opens the fridge door. Or maybe, you actually want to lock the fridge, because an alarm isn't good enough. In that case, the easiest option would be buying a panel-ready fridge and asking your contractor to attach a lock to the panel. A lockable door hasp latch would be the easiest option. But I am sure a good locksmith could construct a prettier solution. Finally, all of this assumes that your kids are at least somewhat trustworthy. If that isn't the case, things get much more difficult. All of the options that I quoted can be defeated: https://www.youtube.com/channel/UCm9K6rby98W8JigLoZOh6FQ When I was a teenager, I wasn't tempted by my parents' booze; but I absolutely would consider any of these security products as a worthy challenge.