I also believe they share the same heater. I owned both , now i only own a air bc of the fact i can always replace my battery and it is way more portable. Both are amazing machines imo.
Solo also has a useful battery level meter, IMO the one in Air is a bit of a joke in that you can't accurately predict the end of useful charge. And the heaters are different, although the function seems basically the same. This difference allows you to tilt the Solo stem to control airflow, Air's 3 rings prevents this, OTOH some see the 'tighter stem' on Air as better. Otherwise I agree with your list.
However, in my case, Solo gets used more by a fair bit. Granted some of that is 'true PA' not available on either Air or current model Solos but otherwise I have both charged and loaded should the urge strike. I find it a better shape for casual hold (much harder to slip out of your hand if you get distracted), find the beep in Air too quiet to notice outside in most cases (another difference?) and enjoy the 'tilt the stem' feature for the prolonged sipping sessions I favor. And I can count on the number of sessions before recharge is needed (with a 'cushion' of a couple extra). I generally practice 'good battery discipline' and prefer timely recharges to battery swaps in practice (although I have a couple of official spares charged to 70% when the need for more sessions between charges as it did several weeks back.
I've also never had Solo fall over on me (although it's clearly possible), Air has toppled so many times I now lay it down...... Perhaps you're more graceful than I am, but the smaller base makes it much less stable around me.
And of course my favorite heat on Solo (step 4) is the one not available on Air (it's the 'hole' in the scale)........I expected no less, my luck runs that way often. If the new model drops a feature, it's the one I liked.......
When size is not an issue, I personally prefer Solo for what I see as solid reasons. When it comes to 'small and compact' I have batter options than Air and use them. Both are solid products for sure, but for my tastes/use Air doesn't replace Solo, given the choice of one or the other I'd stick with Solo over it's 'smaller, reduced feature' brother......provided I still have other options for stealth of course.
The average guy (or gal...) would be well served by either. Serious owners might find useful advantages either way?
OF