Hi, sorry no experience in Macao or Singapore but i live in manila and travel to china via hong kong every month.
No problems in manila. You can bring ecig equipment on the plane. If you get asked by airport security, just tell them its an ecig, they pretty much know what those are. Liquids are subject to airport security regulations same as any other liquid (eg small quantities in a clear bag). Ecigs are legal in the Philippines
Hong Kong is a different story. Sale or possession is illegal here. Having said that, i've had some success with bringing an ego twist + small rebuildable dripping atty (igo-s) or a carto on board a plane, together with maybe 5ml of liquid in an unmarked bottle inside a zip lock bag together with other liquids. Just make sure they're disassembled and that none of your stuff stands out or will call attention. Stealth is highly recommended. All the big
mods and extra liquid goes into checked baggage. Once you make it through airport security, you should be fine.
Just sharing my experience. Follow at your own risk. Hope it works out for you