Humm.
As far as I know, only flying (Qualiflying miles) counts towards elite status so transferring from DC doesn't count. And AC's memebership doesn't valid at CX's lounges.
However, if you can be a OW SAP (2nd tier) before the trip then you can access business class lounge and check-in at business class check-in.
BTW: if you are 4 in a group, it is up to the lounge to grand the access apart from the eleite member (and possibily 1 guess).
Good Luck!
(BTW: Did Diner's offer lounge access? My friend in HK told me he can use lounge due to its DC. And I use lounge at Priority Pass due to my Mastercard)