I don't think you can bank on any partner getting 9W inventory.
Based on what I have learned from others here, I do believe you are right about F and 90% right about J.
Re coach seats though, I already have two booked, so 9W does release them. However, something came up and we must leave one day earlier. I can't check availability directly at 9W, so need to keep checking with AA everyday if not more often. The purpose of this thread was to learn if any particular time of the day is best for such an inquiry.
The only other LON-DEL nonstop bookable with AA miles is BA, which comes with crippling surcharges. Available, but we are trying to avoid them for now.