The two areas you cite are quite nice - except you will need a car (with parking) to live pseudo comfortably in either area. Both areas (depending on WHERE you live in those areas) are considered "up-scale" or wealthy areas. For airport access, the expo garden area is preferable IF you have a vehicle or (as @HFCAMPO notes) can live close to one of the subway stations (but do you REALLY want to drag luggage around the subways?).
In the NE of Kunming is an area called Beichen (correct me if I'm wrong) - which is full of longer-term expats with kids - plethora of language schools, good (for km) pre-schools, primary, middle, and high schools, not to mention a Metro (like BJ) which is convenient IF you have a membership card AND a car (with a DESIGNATED parking space).
Beichen also has a den of expat style restaurants - nothing like BJ (except maybe for Silver Spoon), but good enough to escape home dining occasionally. There's also a bevy of christian churches of various flavors - just ask around at any expat restaurant (with the possible exception of O'Reilly's Bar & Grill), and you'll be inundated with invitations (I'd try to use that to get invited to home dinners - get to know various families). Wicker Basket is a pretty good place to start - both for family restaurant, basic expat groceries & bakery (they have DONUTS...mmmm...), and the owners are christian-ish (they close on Sundays).
Beichen also comes with a fairly warm and friendly community - if you're into communing. For local travel suggestions, talk to @HFCAMPO - that guy is seriously well travelled in Yunnan, and a very interesting character to boot. He can give you the low-down (basic facts) on low-key, low cost, and seriously interesting places to go visit - learn of the rich and diverse culture of this province - and it'll get the family out of the house on weekends - assuming the kids aren't buried in homework and after-school classes like their peers.
And...don't buy a TV...computers work well enough and if the kids have time to watch tv - take them outside in the somewhat FRESH Kunming air (we have our PM2.5 issues also - but NOTHING like BJ...unless you happen to camp next to one of the prolific indoor/outdoor BBQ joints).
If you work from home - a "newer" place is advisable - as the "older" places can have asthmatic network speeds unless you choose a REALLY old place full of old people who fear computers, in which case the internet speed is blazing fast (no neighbors on the highway).
As I write - I can see 6 neighbors WIFI routers - so with computers n smart phones - the desktops work better with direct ethernet connections (or reboot your router daily, to force your router to select a "less busy" frequency spectrum/band.
Good luck - welcome to the city! Trust you will have a pleasant experience - and beware - Kunming is significantly less sophisticated than BJ - so the frequency of locals trying to take economic advantage of the allegedly wealthy foreigners (aka fraud, lying, cheating, stealing) is significantly higher. Beware your personal possessions and valuables when moving. I lost a scanner/printer/fax machine and a variety of other nominal goods to an <plethora of expletives> kunming moving company AND they broke over 80% of my wine glasses (more vicious expletives) and they even managed to bust any furniture which had wheels (like they dropped it off the moving truck...more expletives).
Things may disappear - be prepared.