The Tawainese birds looks like a classic Willow Warbler too.
No, these are not really European birds as all three have significant parts of their breeding range within Asia. Willow Warbler breeds as far east as Eastern Siberia (so some birds actually breed east of HK!), Spotted Flycatcher reaches as far East as Lake Baikal (which is pretty much due north of HK) and Red-backed Shrike as far east as the Altai (being common in n Xinjiang); they do however winter in Africa.
Spotted Flycatcher must be a good candidate for HK.
Paul