As a DEFO you can get an LAX base on the freighter.
SO means HKG base. HKG base has some advantages.
Saying you don't want to be based in HK is generally not a good interview tactic, especially to the HK based interviewer. Both jobs are good and the same seniority list. If you want to work for catahy, you want to work for Cathay. If you only want to work for them if you can be based in a certain base, they will probably not feel that you are that commited to being here.