Graham,
Most of the good birding spots in Shanghai are reachable on a combination of metro + a quick taxi ride. Also, Thirudevaram, McMadd, and Frogfish are all birdforum members living in Shanghai. I'm not sure whether they'll be free on a weekday to join you, but if they're available, they know all the hotspots. If you do require a professional guide, MCaribou offers that service.
MKinHK used to guide in Hong Kong. He doesn't anymore, but I'm sure he can put you in touch with someone who does. You might also want to check out the HK Birdwatching Society Webpage. If they have an outing that weekend, you'd be welcome to join them. You might even find someone on the outing who speaks English!
Can't help you on Tianjin. Never been. But it's a quick 40 minute train ride to/from Beijing. Jesper Hornskov, who's based out of Beijing, guides in that area. His email is goodbirdmail(at)gmail.com or goodbirdmail(at)126.com. If he can't get to you, he can probably hook you up.