@cuk,
The sorting buttons (including the inline commenting) are not available for the default comments pagination type [1][2][3]... It's only active for [Load more] and other AJAX pagination types. So navigate to Dashboard > Settings > Discussions admin page, and uncheck the "Break comments into pages with…" option.
It's described here: https://wpdiscuz.com/community/f-a-q/if-the-wpdiscuz-sorting-buttons-are-missing/
Please watch this video: https://www.screencast.com/t/MUa16OXy6O
Regarding the second issue, I'll let you know a bit letter.