Just called Plat CSR, was told that CX was still a transfer partner. The CSR told me that she could transfer points over but since I wasn't planning to do so, this was only a hypothetical possibility.

CSR transferred me to MR who confirmed that CX is still a valid transfer partner. But, again, this is only hypothetical as in order to be sure I'd have to actually try to transfer points and I'm not feeling very "guinea piggish" right now.

Neither AMEX nor MR could see any info on AsiaMiles, per se, nor had any insight into what's going on with the website.

So for now I guess the only way to know for sure is for someone to call in and try to transfer points, then monitor their AM/MP accounts to see if the transfer actually went through.

EDIT: Forgot to mention that AMEX CSR told me they would "open a ticket" on the website issue.