The HK list includes both these two species, but no subspecies information.
Japanese Bush Warbler 日本樹鶯 Horornis diphone
Manchurian Bush Warbler 遠東樹鶯 Horornis borealis
IOC has ssp canturians included in Japanese Bush Warbler 日本樹鶯 Horornis diphone, and I beleive this is the subspecies in the photos.
Very little id information is available to the birdwatching community. I hope the HKBWS record committee can help on the id of the various species and subspecies in HK.
HF Cheung
