Yeh I'd say they're all blue areas except for Sale which I'd consider red. Pretty sure on the last study I read it said Cheadle was City's area with the most season tickets, and Sale was United's. I'm sure that's also a reflection that they're slightly wealthier areas than the other Manchester suburbs you listed.
I guess the point I'm making is that I'd consider City's heartland as south Manchester and east Manchester. But the club seem to have forgotten the south Manchester roots we had for 80 odd years.
Unless they're classing Trafford as "west Manchester" and the city of Manchester itself as "east Manchester". But to me east Manchster is Droylsdon, Clayton, Tameside basically. I know there are loads of blues up that way, but there's equally loads in Fallowfield, Moss Side, Didsbury, Longsight, Levenshulme, Bernage etc. Personally I'd consider those areas as south Manchester, but the club never seems to engage with those communities any more.