You should test the Easyblog and Easydiscuss page because the Easysocial page does not have support schema data.

But all the pages should support the basics of metadata e.g. meta title and meta description.

I have this extension that have support for EasyBlog only but I have not configured it yet https://www.tassos.gr/joomla-extensions/google-structured-data-markup

I see, then I am not sure how this 3rd party plugin "Google Structured Data" works.

Yes this is important for all Joomla/Stackideas customers. First step is to be on top of Google SERPS second step is that you are seen well in the top search results so people click on the link and come to your site. So this is as important as be on top of SERPs!

So you should have ratings that are visable and give good impression.

Thats why for example ratings/reviews can be of high importance for EB/ES/ED blogs, ads (marketplace), events, pages, groups etc a n d be working with Rich Results

Easyblog and Easydiscuss should have the rating on the Google search as long as you have activated the rating feature.

Unfortunately, we do not have this in Easysocial at this point of time.