I have a set of functions that I found online which add a meta box for templates to my WP Post editor and it works perfectly (http://pastebin.com/0WdPAWM1).
I tried to modify it to be applied to an array which includes the LearnDash custom post types I need the metabox to also show up for (http://pastebin.com/755bEtJc), but all I managed to do was to get the metabox to appear. Unfortunately, the drop-down menu didn’t populate (it only shows the templates on the normal “post” editor).
I know that it is just my ignorance of PHP keeping me back, but I tried to replace every instance of ‘post’ in the original set of functions to $types which is my array variable and that didn’t work either.
These are the custom post types I need the template selector on:
'sfwd-courses', 'sfwd-lessons', 'sfwd-topics', 'sfwd-quiz'