Spot 1: No way. The ankou chamber has no sufficiently good spots to stand and range without getting attacked.
Spot 2: Again, there aren't really any good places to stand where you won't get attacked in the cockroach area.
Spot 3: You make a point saying it would be crowded, however this is the best spot on your list. Try picking the lowest lootshare non members world.
Spot 4: never go into the wild to train unless you are 100% not afraid of Revenants.
I have no suggestions myself that wouldn't be bad so out of the 3 you have I would go with 3.