... I could still designate users that could only affect certain categories, and add content only to those categories on the front end. Is this the case? 4) If content is shared, does this mean that all sites will run from same database tables, all with the same prefix? If possible, is there any ...

... sites will load same categories and articles, but each site will display articles only from selected category. Menus should be different in this case because you setup which category to display in menu item settings.

... are used by them. Is there a way to sync them in one or the other way? No, synchronization of login and profile changes is done via same case-insensitivie username. So user should have accounts with same usernames and passwords in both systems. -Is it possible to put the forum-only users ...

You can only copy database tables into another or same database with different prefix.
Copy of files is not possible.
MightySites is intended (but not limited) to use same Joomla installation for all sites, so in case of database copy you can quickly setup new site with own database data.

... optionally clone the database tables of master site for sub site. And are they all controllable/settings controlled from the master site? In my case, In my case this would be the easiest way to manage things as they should be the same across all sub sites, except for the menu which can be controlled ...

... styles etc. available from the master site across all sub sites? And are they all controllable/settings controlled from the master site? In my case, In my case this would be the easiest way to manage things as they should be the same across all sub sites, except for the menu which can be controlled ...

It can be used as usual if you don't need to share its data across sites.
In case of sharing support please create a ticket in our Support Center and attach this extension, we will add a support for it.

In this case EasyBlog data can be shared.

... will be in default Registered usergroup and won't be able to see this content. If phpBB user logs in Joomla and there is no same Joomla user with case-insensitive username or emaIl - the Joomla user is auto-created.

... profile in the forum will cause the person's CB profile to be displayed 3. Link to send a phpbb pm appears in a persons CB. Is this also the case if the ability to send an email to a member is turned of in CB? 4. If a person registers in Joomla a similar member is created in phpbb3 automatically. ...