Hong kong disneyland ticket

I think it's possible. ''pick up your tickets starting from 1 hour after you have purchased online" means the ticket cannot be picked up within one hour after the successful online purchase, not that you have to pick it up within an hour after booking. You can pick it up just before entering.
But I recommend you to book online a fews day before your departure, for I'm not sure if the ticket will be valid or not after a month. Maybe you can consult the Hong Kong Disneyland for the info.