Hello @MelissaFisher94 - 

Each discussion board has its own settings and it's not possible to change them as an entire group.

One thing you might do is set up one discussion board with your preferred settings, and then duplicate that board. After you duplicate it, you can change the question/prompt and information in the rich content editor. Discussion boards (along with all other assignments & quizzes) are automatically unpublished until you choose to publish them.

You can also do a bulk update to due dates and availability dates.

Hope this helps!