The A340-600s are likely to replace most of the 10 existing -300s. Possibly up to 3 -300s may be retained to allow limited route expansion. At the moment, I believe that 2 of the 3 stored Classics are being considered for use on bucket-and-spade routes for Virgin Holidays. As VAA no longer has the 742 on its AOC, a third-party operator would have to operate the aeroplanes on VAA's behalf. Where the crews would come from is another question, as most (but not all) of the Virgin ex-Classic crews have retrained or have left the company for pastures new - whether voluntarily or not.
Personally, I wouldn't put too much faith in this project coming to fruition, but you never know!