err..No...If you start on the Freighter Fleet there is no requirement to base yourself in HKG. Moreover, the whole concept of the Freight operation is to use based people on salaries the company perceives to be competitive with local base market conditions. Unfortunately, the company perceive a year 1 Freighter FO's salary to be nothing like the $95,000 mentioned.
As regards command, all depends on the growth rate of Cathay. However, bear in mind 2 things. Firstly, even if you join the based Freight Fleet as an FO, your seniority number is on the mainline list below any persons who joined prior to you, including SOs (I would guess about 700 folks are ahead of you). Secondly, should you decide that HKG is not for you or your family then command propects become accordingly limited to you having the seniority to bid for a based command slot, which I understand are much sought after in the USA.
Good Luck.