Minnows are the new users here, dolphins are the medium sized accounts with >5k SP (steem power), and whales have over 100k SP. @minnowsupport is a communal bot that upvotes the post you can submit via a command at the PALnet discord server every 12 hrs, and it is supported by members of the steemit community that loan it SP to help the minnows.

For your last question, I've never heard anyone ask for a handwritten auth with a photo, but I'm sure that would help get people to connect with you more personally, or possibly serve as proof if someone is claiming to be a fairly well-known figure.