On the big post option, it shows the category and date, but the date is formatted as "24.12.2017" instead of the way my general settings has it. How do I get it changed to read "December 24, 2017"?
You can change that date format from the following file:
fox \ loop \ content-big.php line 18
line 18 - replace "d.m.Y " with "F j, Y "
Then you would need to remove the code for the date i.e. line 17 - 19
Then use the get the author method i.e. https://developer.wordpress.org/reference/functions/get_the_author/ to add the author.