I understand the desire to have a night in Paris (one of my favorite cities), especially if your wife has never been. Just be prepared for an early departure the next morning to arrive at CDG by 8:30 am for your flight check in. If going by taxi, I wouldn't leave any later than 7:30 AM. Logistically, a taxi for the 4 of you makes the most sense, but one never knows what kind of traffic you'll face on the road. That could be an argument to take the Metro/RER to the airport (rather than a taxi), which may bring to bear on your choice of hotel location, i.e., ideally one that is near an RER Metro stop. That would be more logistically complicated than a taxi, especially with mobility challenges, bags to schlep, stairs instead of elevators at the Metro station, whether you'll need to change trains, whether you can all find seats, etc. But, the advantage of the RER is that you will not be impacted by traffic on the ground. (Disclaimer: I've never taken the RER to/from CDG. Maybe there are elevators or escalators in the RER stations. I just don't know.)
Now for a cautionary tale (and some context for my comments): upon our arrival at CDG in May 2023 (around noon on a Tues), we took a taxi into central Paris and it took TWO hours. Perhaps our experience was an outlier, but every time I've headed to CDG from Paris, the traffic gets worse. Thankfully, we had nowhere to be (other than our hotel), no train to catch, etc. But, if we were headed to the airport under those circumstances, we might have missed our flight.
Perhaps some of the Paris locals on the forum can advise re: traffic to CDG at that hour. Also, it might depend on which day of the week you'll be headed to CDG. I suspect weekdays are likely worse.