The problem I have with your list is that it treats depression as a black box, and the solution is to throw random things at it until something sticks. There are things that can be done to better identify underlying causes. For example, your list should touch on deficiencies in iron and B12. Your symptoms can also be a clue as to which neurotransmitters are involved.
Solutions need to tie back to causes. Vitamin D supplements are useful if you have a substantial Vitamin D deficiency. All the serotonin supplements in the world aren't going to help if your issue isn't a shortage of serotonin or its precursors. Understanding how different solutions relate to causes (and therefore relate to each other) gives you a smarter way to approach solutions.
Full disclosure.. my psychiatrist wife and I are working on a book to help people approach mental health care in a more systematic way, trying to take the magic black box out of it. A big part is also on how you can best work with the resources you have available (we're in Canada, so different but comparable range of limitations as in the UK).