Having been to Coll and Colonsay in the past couple of months I would guess that they will never be manned full time and if it was I wouldn`t fancy that job with only the midgies for company most of the day.
Good luck trying to keep anything about these fields positive, its been tried before.
Fantastic places to visit, you can get a multi landing card at Oban (4 landings I think it was) for £20.