TS, I am curious why you need to place deposit???
I bought lens from Hong Kong before, I just need to email or call up the shop to check of they have the item(s) I want and if they have I will tell them when I will go to their shop to pick up the items.
I am not sure which shop you have committed, but I know one that sell 70-200 VR2 few hundreds cheaper than you listed.
Anyway, enjoy your trip and shopping spree. For the boxes, suggest you fold them and bring back as it is easier to sell the items off in case you regretted.