Query

Each peson providing comments needs to insert their own annotation (sticky note, whatever).
Upon creation, an annotation assigns the login name associated with the Acrobat application being used to place the annotation.

Someone else placing text into another's annotation precludes sorting annotations by author.

With more than one individual providing text input to the comment (sticky note ?) you could have each end their text with their initials.
However, doing so means identification of who has done what becomes really labor intensive and error prone.

In Acrobat's Preferences, look over the Commenting category.
You can select options such as:
Annotation pop-ups visible as document is scrolled
Auto open comment pop-ups for comments (annotations) other than notes (stick notes)
Auto open pop-ups on mouse rollover
Turn off use of login name for Author
Have new pop-ups align to edge of document
and more...

Having a commonality in the usage of these by those who are collaborating on something can be useful.


Yes.
To set the stage...
First get into Acrobat's Preferences ( Edit > Preferences).
Select Category "Identity".
The top line in the Identity dialog wll show the "Login Name" of the user (if a login is used - typically, in the workplace a login is used).
Additionally, the Name, Title, Organization Name, Organization Unit, and Email Address can be given values.
This is particularly useful when one goes about creating an Adobe self-sign digital ID.

When you have logged into the computer, open Acrobat and go about adding annotations the "Login Name" is the default "Author" of the annotation.
So, when you login as user "abc123" any annotations made will use the value "abc123" for the "Author" of the annotation.

Open the Comments List to view annotations. There, you can sort on annotation type, author, page, date, etc.
You can also tell Acrobat to show or hide annotations based on type, author, etc.

Using the features available in the Comments List you can configure comment reports.
Something to play with to see it an available report output would meet report needs.

Be well...