Hi @Margo
Yes I have standard support plan having recently purchased forms, perhaps I've asked too much for a single forum question.
However, after reformatting my code and implementing the requirejs method from your post here: Load external script files via HTML control I have now reduced the issue to a single error after the script is being included:
$(...).typeahead is not a function
I have referenced the same external script in a vanilla aspx page on the same SharePoint environment and it is working so I know it's not an issue with the external js file.
Would you still recommend sending a support request?
Thanks,
Andrew