If you're doing such a low mileage that the tyres are lasting 7 years I would be inclined to say that tread life is less important since, as you have found, age gets them before wear.
Rather than going for a premium tyre perhaps something cheaper would give better value in the long run?
Of the tyres you mention Continental are generally praised on the Omega, the others less so, but they are at the pricey end of the market. I have used SportContact 3's and they provide good grip in all conditions, low noise and reasonable wear rates for a grippy tyre.
30K is a long life to expect from a tyre on an Omega, IMHO, and you won't get near that from a set of SC3s, IME, but we all drive differently and have different expectations, and hence all have a different answer as to which tyre is best.
I have used various Dunlop tyres. More noise but generally good other than that. I have Kumho KU31s on at the moment and they are fine and competitively priced, IMHO, but, again, won't last 30k.
Members have reported variable results with Falken tyres. They tend to tramline quite badly so might be worth giving a wide berth.
I tend to go for the more grippy end of the tyre spec. and am less concerned about mileage so the above might not be much use to you. I'm sure someone can expand on the above though.

Kevin