I was thinking about this topic further while I was driving today. I return to see that Pat is thinking reviving the 9-7 could be the best course of action and I agree. But, since I gave this thought, I'm going to write what I was thinking anyway in case the used engine idea does not fly.
I am going to retract my recommendation of the Mazda5. I think this will be seen as too samll and too underpowered (which it is.)
Looking at Gizzfamily history the recent vehicles where Buick Rendezvous and Saab 9-7. Both of which were liked, before their demise. I think the Gizzfamily likes vehicles with some size, power and presence. My thought here is further encouraged by the admission of the like of the Ford Edge, specifically with the largest engine option. This a car built on Ford's largest unibody frame. Since it is the short wheelbase version of that frame, lets call it a large medium vehicle or small large vehicle but either way, it's bigger than medium.
The desired spend here is $23k, maximum. USA Today says that the average transaction price of a new car in 2015 is $33.5k.
I think the real question is:
What vehicle can I find that is larger (and more powerful) than the average vehicle but retails for less than the average vehicle?
Two choices that come right to the top for me are:
Dodge Caravan, entry model (already dismissed)
Kia Sedona Minivan, entry model (already dismissed)
If all minivans are dismissed, that will leave the SUV's and price wise you are looking more at the small/medium (and small engine optioned) SUV rather than the larger SUV. Your price may get you into an entry Escape, Equinox, etc but not a loaded version and certainly not an Edge, Traverse, etc even entry model.
We all want the same which is seating for 8, towing of 5k lbs and 30mpg for less than average car dollars.
It's not out there.
Your sister in law has a '14 Chrysler and though she does not exactly love it, I commend here for the choice because in her situation of 3 kids and 2 dogs, it was likely the best choice/compromise out there.
The Chevy Equinox may be worth looking more into. You might be able to swing a V6 version in your price range if you stay with 2015 left over models.