ps2 can be easily modified to play all regions as well, i have had 3 japanese ps2 and played pal, us, korea, hk and every ps2/ps1 games, also, note, a lot of pal uk games are inferior to their japanese/us counterpart, thick black borders and slower game play /frame rate (60 fps vs 50fps) hence, why i have been a big importer ofr games for last 25 years
you can easily get a decent dvd player modified to play all regions, just don't go to fortress or broadway, independent places such as CCAV in mk have many dvd players which play all region, bluray is different, better if you get a bluray/dvd player in HK, plays us, japanese and hk bluray while your ps3 plays uk bluray
For movies (or tv series), if you got a multi-system blu-ray/dvd player (common in HK), what regional coding that blu-ray/dvd has isn't an issue.
The key is what sort of DVDs do you intend to import to HK from Amazon? I've bought specialty DVDs on Amazon frequently and there has been no issue about them selling to HK. The only potential issue is if you buy, not directly from Amazon, but through the second-hand sellers on Amazon, they might have regional restrictions which prevents them from selling their items to your area of the world.