Should I actually give credits to the reviewers who contributed to the new version?
Yes. If we look at the bottom of this Stack Exchange page, we have the footer:
site design / logo © [year] Stack Exchange Inc; user contributions licensed under cc by-sa 3.0 with attribution required
Under the Creative Commons link, "CC BY-SA 3.0", we have the following description for attributing:
Attribution — You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
The original text has some popups, that further explain the emphasized text above. More specifically 'indicate if changes were made' links to a "best practices for attribution" page. Which further describes attributing. They have an example under the header "this is an ideal attribution", that shows what a good attribution is, and why:
"Creative Commons 10th Birthday Celebration San Francisco" by tvol is
licensed under CC BY 2.0
Title? "Creative Commons 10th Birthday Celebration San Francisco"
Author? "tvol" - linked to his profile page
Source? "Creative Commons 10th Birthday Celebration San Francisco" - linked to original Flickr page
License? "CC BY 2.0" - linked to license deed
This is good, but doesn't explain two things.
What to do in the case that an answer doesn't have a title.
In these cases "best practices for attribution" says not to worry about including a non-existent title:
If a title was provided for the material, include it. Sometimes a title is not provided; in that case, don't worry about it.
You've derived from the answers work. How do you correctly explain this?
"Best practices for attribution" further explains this, and extends on the above attribution example:
This work, "90fied", is a derivative of "Creative Commons 10th Birthday Celebration San Francisco" by tvol, used under CC BY. "90fied" is licensed under CC BY by [Your name here].
Original Title, Author, Source, and License are all noted
Derivative? "This work, "90fied", is a derivative of..."
New author of the derivative work is also noted
IANAL, but I think it's safe to attribute with:
This code is derived from the answers to my previous post, attributing person A and person B. This derivative, and all previous ones, have been licensed under CC BY-SA 3.0.
I'm unsure if you can remove the licence part, as that should be implied by all the code being posted on Code Review.