Is it necessary that the publication be a writing ?, or can they be videos of drawing process uploaded to youtube?
I would say that any content is OK, as long as it's decent :)
The bid will be returned if you are not on the whitelist. From the @ocd discord:
What is the minimum necessary to delegate?
I presume there is no minimum, but I wouldn't consider < 50 SP being that useful. You can check the delegations to ocdb on https://steemworld.org/@ocdb