You're not required to link your work at all, except for on contest days, and even then only IF you want to enter the contest. To further answer your questions:

Including the link is optional, and you don't need to post a passkey, since we're on the honor system. The only exception is when entering the contest on contest days.
Yes, your passkeyed items will show up on the entry list. If someone clicks on the link, they will just be prompted for a passkey.

Crys

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