If Britain gets Luzon in 7 years war this means that the series of Famine that happened in Luzon in the aftermath will be butterflied and Britain would get the old trade route of Malaya/Java to Ryukyu, would this mean that the Anglo-Dutch treaty will be butterflied as well and Britain would retain Sumatra and Java ITTL..although Britain can get Sarawak to secure the old trade route.
I don't think Britain can get into China trade as the territories that British get here in the Malay archipelago are hostile to the Chinese, we can kiss goodbye to the Opium wars of China.