Reliable, fuel-efficient, good handling

Sounds like another wagon type car would work well for you.

I agree with your accessement of the Buick TourX -- very nice car in many ways but L-o-n-g and not that fuel efficient. Also pricy but thanks to poor sales it discounts are easily had. Will probably be orphaned after this year. After driving one when they 1st came out, I felt the 2019 Outback was a better car by a small margin (currently I drive a 2015 Outback).

Speaking of Outbacks, given that you are a satisfied long term owner of Subaru wagon I think you definitely should drive both the Gen 5 (2015 - 2019) and Gen 6 (2020) Outbacks. While there are a few nits, the Gen 6 (2020) is an improvement in most regards over Gen 5. To improve handling upgrade your tires. If you get a Gen 5, spend $100 to get an easily installed 19 or 20 mm Subaru STI rear sway bar for noticiably flatter cornering.

With the 2.5s your mpg and acceleration will be similar to the current Subie. If you need more ommph, get the a Gen 5 H6 engine or Gen 6 XT with turbo. Of course you you will get few mgp with the larger engine. Gobs of owner info on new Outbacks here: https://www.subaruoutback.org/forums/gen-6-2020-future.233/
https://www.subaruoutback.org/forums/gen-5-2015-2019.138/

Subies remain quite reliable although there have been some issues with late model Subies -- most notably a small percentage may lose oil (leaks or burn it). That said the early 2000 Subies had a reputation for bad bearings and blown head gaskets, so no car is perfect. To a significant degree your reliablity is partially dependant on the luck of the draw and maintenance.

IF the Outback doesn't fill your bucket and you are OK with a sedan, then I'd steer you to the Accord followed by a Mazda 6. Both should tick off most your boxes but the Accord will get better mpg and have more room (important with growing kiddos). Also both are reliable but given all the new electronic do-dads on new cars, the is more to go arwy and more complaints when compared to a car build 15 yrs ago.

Regarding Android Auto: that seems to be glitchy for lots cars and users. Just be sure to check your android phone for compatability. If you encounter difficulties, have the dealer set it up to your satisfaction before purchase.

Happy car hunting and please return to let us know what you end up with.

Sea-Dan has an excellent post above^^. He is THE expert on Subarus. Make sure Android Auto works well with your phone before buying. The dealership will likely blame your phone for being the issue I've heard.

The Outback is a good car, but it really prioritizes comfort over sportiness. Upgrading the tires will get you better grip handling, but still won't improve steering feel/feedback enough. I personally care more about feel and feedback from the road more than grip numbers. Other than handling the car is near perfect. Test drive one to make sure you like the handling. Chances are, if you didn't like the handling of the Legacy sedan, then you probably won't like the Outback's handling.

The Civic might be a little too small when your kids get taller. It is a great car aside from the infotainment system, which would actually be a deal-breaker for me because it feels so old. It does have Android Auto however.

I don't see a reason to get the Civic when you could get a new Honda Insight, which is a better-looking Civic with better gas mileage and a better interior.

The Accord fits the bill pretty well. It has the same engine as the Civic (1.5t), so they would both have the same problem unless you got the 2.0T. I haven't heard of any coolant problems, but the oil dilution is one I have heard of. If you don't make many small 1-mile trips repeatedly in extremely cold temperatures, then I wouldn't worry about it. That is when the problem sometimes arises. They also have a hybrid Accord, which I would probably buy over the 1.5t. Gets mid-40s mpgs to nearly 50 mpg.

The Camry is worth a look. They improved the handling a lot in the current generation. I would completely ignore the 2.5L base engine and get the hybrid. Look at the XSE hybrid to get mid-40 mpgs.

Lastly, I have to mention that the Kia and Mazda will likely be very reliable. I am pretty confident that the Mazda will be more reliable than any of the Hondas. They have been using the same three engines for many years and two of them are naturally aspirated. The reliability ratings have been above Honda for years. However, the Toyota can't really be beat for reilability.

So, I have to recommend the Mazda 6. I think it would be a tie between the Mazda 6, Accord, and Camry. The Mazda has fantastic steering feel and has a very nice interior. The only bad things are that the infotainment system is a little old at this point (does offer Android Auto), backseat might be a little tighter, and it isn't available in a hybrid.

The new Kia K5 (2021) and Hyundai Sonata are excellent cars that people are saying handle well. Their interiors are also really good, almost to the level of Mazda. Their tech features are the best in the segment by far. They will likely be the best in the segment. I would wait until you can test drive them before you make the purchase.

SO, the Mazda 6 and Honda Accord are my two top picks. If I were you, I'd probably get the Accord, likely the hybrid Touring trim. On the test drive of the Accord hybrid, be sure to chuck it into a corner quickly to test the grip. The eco tires might not be good enough for you. The tires are a major reason the car gets great mileage, so once you put on a set of non-eco tires on a hybrid car the mileage will drop a lot.