Not necessarily charge cards; what you said failed to take into account some co-branded, top-tier AMEX credit cards issued in China. I visited this great lounge on 12 Oct before my Virgin Australia HKG-MEL flight, with my China Merchants Bank (CMB) American Express Platinum Card. As AMEX is currently not allowed to issue cards directly in China, all AMEX cards in the country are co-branded credit cards issued with select bank partners, such as CMB, and no charge cards are on the market yet.
No. The policy is the same as at USA Centurion lounges. You must present a Centurion or Platinum charge card, or be the guest of someone who presents one of those cards.