Hey there,
I am really sorry for the delay of this reply as it is a public holidays for us here.
Is it possible for this display label for each input field?
Do you mean you would like to display like following format?
Label | value
Select a Category: | select category
Topic: | enter your topic
If yes, you have to modify this php file
JoomlaFolder/modules/mod_easydiscuss_quickquestion/tmpl/default.php
Why do I see the default categories instead of the "Select category" category in the category selection box?
Because you set one of the category as default from backend > Easydiscuss > categories , try run this following SQL query into your database.
// Replace #__ to your table prefix
UPDATE `#__discuss_category` set `default` = 0 where `default` = 1;