Non-intuitive Error message when creating new blog post

Steps:

• install blog post using essentials and create a new document of type blog post
• enter data in each field except author
• click save and close
• error message is displayed as shown in screen shot which talks about 'a link'. There is no other feedback which field is wrong.

• selecting an author resolves the error (I thought 'link' referred to another document...)

Making only the last field mandatory is very uncommon.
Can you move field Authors up? And make field title also mandatory.
Can we make the link picker show error feedback like other fields? (see second screenshot)

Next I published the blog successfully. However I cannot view the blog: "preview is not available"

(let's create sub issues based on what is feasible)