I have no experience specifically with Arts Council, but I'll try to give some general advice.
Q: Who should my referees address their recommendation letters to?
A: Referees may address the competent body in general. For example:
Q: If I need to have letters to support press documents that I was involved in but not directly mentioned will these be considered reference letters too?
For the attention of Arts Council:
Regarding the application of Mr ...
A: Since you have two pages for each supporting document, you may put extract from Guardian article on the first page and small letter expaining your role on the second page. This is a useful trick if your name is not directly mentioned.
Q: Will I be penalised for having too many letters from industry professionals?
A: I think, it depends. If all letters are very different and cover many different areas - it should be fine. If letters are all the same - it looks like you have nothing else to add and simply filling the space.
Q: -I do not have a degree... is this a major issue?
A: Normally, it's not an issue. I was endorsed by Tech Nation while having a non-tech degree. It might be worth adding a document to explain how did you learn your craft.
I suggest to wait for some replies from talents in arts, just in case.
I wish you best of luck.