If *A travel is not likely going forward then I would concentrate on getting the most miles out of the trip and not worry about status. But you need to do some homework as a high earn rate could be accompanied by poor redemption rates/options for a particular airline.

On Alaska you would earn 45,656 miles on an SQ D class ticket CPH/SIN/CHC return. That would be enough for a one way PE ticket on BA from the UK to North America. Being based in Europe the redemption opportunities with AS are not great.

You might want to look at a *A carrier in Europe as the redemption options would be much better than AS. Eg, LH, A3. And I would definitely look at SQ too.