Unfortunately (yes, in 2020), this is still not possible via the API. It is possible to see what the suggested edit is (added or removed text, changed style, etc.) from the API, but you can't see who made the edit or when they made the edit.
The work around I am currently using is (does not work retroactively):
- Subscribe to Google Doc changes via email (Gmail specifically)
- Use the Gmail API to get all emails received from comments-noreply@docs.google.com
- Parse the email contents to get comments AND suggestions, including when, who, and what
- Now that you have the suggestions and comments, you can do whatever you want with it. Save it to Google spreadsheet, save it to .csv, etc.
This answers the first part of your question: programmatically enumerating them. As for programmatically accepting them, currently not possible through the API. I haven't done it, but I believe it is possible to do it via JavaScript.