In order to not lost those ownership data, you have to enable these Easydiscuss/Easyblog user plugin on the site.

User - EasyDiscuss Users plugin - Enabled
1. Transfer this user tag ownership to your site admin
2. Transfer this user comment ownership to your site admin
3. Transfer this user post ownership to your site admin

4. Remove this user badges data from database
5. Remove this user Conversations from database
6. Remove this user Moderator data from database
7. Remove this user Likes from database
8. Remove this user subscription from database
9. Remove this user Votes from database
10. Remove this user data from database

User - EasyBlog Users plugin - Enabled
1. Transfer this user category ownership to your site admin
2. Transfer this user tag ownership to your site admin
3. Transfer this user comment ownership to your site admin
4. Transfer this user post ownership to your site admin

5. Remove this user ACL data from database
6. Remove this user Adsense Setting from database
7. Remove this user Feedburner Setting from database
8. Remove this user Adsense Setting from database
9. Remove this user OAuth Setting from database
10. Remove this user Featured Blogger from database
11. Remove this user TeamBlog User from database
12. Remove this user Blogger Subscription from database
13. Remove this user data from database

User - EasySocial - Enabled
1. Remove this user indexed search data from smart search database

Regarding this Easysocial, without these user plugin, when the admin delete this user from backend through Easysocial user listing page, it will remove all the data belong to this user from the database.

Can you by any chance provide SQL query?

Hm, unfortunately that was not possible to provider these SQL query straight away is because most of the sql is not straight forward, it needed some PHP part to render the value as well.

Thank you for detailed answer.
If I understand you correctly the ownership of ES: user post, comments & user tag will be transferred to site Admin when EasyDiscuss Users plugin is enabled.

This brings additional questions:

• are these posts, tags and comments going to remain published on front end?
  
• what site admin user account is used to assign new ownership? Lets say I have more site admins on the site.
  

Thank you for detailed answer.
If I understand you correctly the ownership of ES: user post, comments & user tag will be transferred to site Admin when EasyDiscuss Users plugin is enabled.

Hm, nope, maybe i try explain this way, you can better understand this :

Easyblog
--------------
1. Some of the existing blog post created by UserA
2. Admin delete this UserA account
3. This EasyBlog Users plugin will transfer all his post owner to Superadmin, you can configure this ownership from backend > Easyblog > setting > general > system > http://take.ms/0rbbB

EasyDiscuss
------------------
1. Some of the existing discussion post created by User A
2. Admin delete this UserA account
3. This EasyDiscuss Users plugin will transfer all his post owner to Superadmin, you can configure this ownership from backend > Easydiscuss > setting > advanced > general > http://take.ms/PbmR0W

EasySocial
---------------
1. admin delete UserA account
2. System will delete all his stream and comment data from database
3. For those group/event/page will remain on the site, but the ownership still remain that creator id but it will show as guest, this is what i tested in my locally, it seems like something is not right for this part, i will lock this into our issue tracker.

are these posts, tags and comments going to remain published on front end?

If you referring Easyblog and Easydiscuss, yes, it will remain to published on the frontend.

what site admin user account is used to assign new ownership? Lets say I have more site admins on the site.

Currently only available to configure this for EasyBlog and Easydiscuss component.

Hi,

Just wan to know, is the no.3 issue here fixed yet?
Thanks:D

EasySocial
---------------

3. For those group/event/page will remain on the site, but the ownership still remain that creator id but it will show as guest, this is what i tested in my locally, it seems like something is not right for this part, i will lock this into our issue tracker.

Just wan to know, is the no.3 issue here fixed yet?
Thanks:D

Yes, this issue already fixed.