What is known about management groups?

There is some documentation available about this topic.

I would like to know:
What are all the features available to a user for belonging to a group created in owncloud?

If I share a folder with a group, the permissions for all users in that group are respected. And if I change the permissions to the folder, are they inherited?

Thanks in advance

Yes. Any permission changes are inherited to all files and subfolders.