Anthony for a container mix with a long life, which is surely what you want for container trees, I would recommend you look at the postings on the container forums. The mixes you are using I would think would become compacted and have a serious drainage problem as the organic portions breakdown. Al

Your mix should work fine- all mixes loose drainage capacity over time but coconut fiber is probably about as good as anything to help drainage short term. One nice thing about using sand is that it doesn't break down but it's down side is its weight, unless you're trying to prevent blow-over.

Sometimes people mean by manure, cow manure, sometimes they mean horse stable waste. Horse stable waste usually has lots of pine shavings in it which will help keep soil loose until it breaks down.