In my opinion what will happen is, and the order will be:
1) Anyone with 2 or more CC tickets
2) Season ticket holders with ACS and CC ticket
3) Members with CC
4) Season tickets with CC
The reason I think this is because if only 7000 ST Holders were in CC ACS/12000 in FA Cup ACS, and members get priority over season tickets you can bet every penny in your pocket that every single season ticket holder next year will sign up for both ACS competitions.
Also in terms of allocation. If out of the 31,000 ticket we got, the fans get say 25,000. Then there will not be more than 5000, who have been to 2+ games in the CC, as most of these who have been to an away, will have been the home leg against City too. Leaving 20,000. Minus 7000 ST CC ACS. 13,000 remaining for the members.
Seems logical to me.