[Streggi]

For #1, also save the main add-on settings (not just series selection), then go back in.
I was wondering if selecting a bunch of series would cause a problem. Can you try selecting just a few items then report on #5 again? You may also try closing Kodi, removing that setting from the file (you can just delete the line), then start Kodi and try again.

This confusingly named setting only affects episode 'fanart' automatically pulled from web services, not downloading existing thumbs nor matching local artwork, so you probably don't need to enable it for everything. I've rearranged settings for the next version to make that more clear.

 Sorry, should have been clearer.  I tried selecting, exiting, and going back in and that doesn't work either. 

I tried selecting a few series and the setting did change to:

 281511|279536|311945 :


    <setting id="autoaddepisodes_list">281511|279536|311945</setting>

Deleting the line, restarting and the trying to select didn't help - it went to:

 :
<setting id="autoaddepisodes_list" default="true"></setting>

This confusingly named setting only affects episode 'fanart' automatically pulled from web services, not downloading existing thumbs nor matching local artwork, so you probably don't need to enable it for everything. 

you've got me confused now!  I managed to get most of my episode thumbs e.g. episode -s01e01 -thumb.jpg downloaded to my HDDs - how did I manager this and what setting controls this?  This has been a lifesaver, but I can't get any more thumbs downloaderd.