I've been to China three times this year so far and it's getting harder and harder. I have Private Internet Access and pretty much every endpoint (they have a lot) was blocked by China. I found one obscure one on a weird port in Romania (?) that worked but performance was bad if course. I think i'll set up pfSense or something at home and VPN back to just go out there. Since our corporate VPN isn't blocked it makes me think they are just blocking known VPN CIDR subnets rather than doing deep-packet inspection to look for tunnels or IPSEC.
The phone thing does indeed work. My AT&T phone gets everything and performance is reasonable. I can't tether with an international plan but that HK workaround sounds good.
How much data per month can you get in China with an HK plan and tethering?