Transit in 3rd region = OK? CPH-PEK(transit)-CAN CAN-HKG(transit)-CPH? Thanx for any help : )

Chris, if so, you cannot enjoy the 144 hour free transit in Guangzhou. If your total layover in PEK and CAN is less than 24 hours, you can enjoy the 24 hour direct transit in China, and then no visa will be needed. Otherwise, you need to apply for a visa for that.