Vanessa Marie Jencks. There's no straight answer to your question. Although an ED should be reasonably straightforward, as far as B or O (volunteer) is concerned these are dependent on who you are working for and their relationship with their respective immigration offices. There's no 'one size fits all' for these situations
With regards to point 2, have you approached any volunteer foundations yet? They would be able to tell you which volunteer visas are available in specific areas.
John Stanners. That's no big deal. I think in the US it seems to be a problem. I know in Australia it's very easy (unless of course, you're a crim! 😆)
Alex J Murphy. One small piece of advice. My wife works for a company in Bangkok which employs many overseas skilled workers. Three Mauritian guys just went home for Christmas and New Year before the Dec 22 changes. My wife spent a large chunk of the Xmas/New Year period trying to organise the return of these guys. Finally got all the TPs, hotel etc organised, but the TPs took several attempts, being rejected for no apparent reason, so she just kept resubmitting the same information and finally they all came to fruition. So just let your wife know if the first attempt fails, to just keep trying
John-Paul Riva. Withdrawing 800k from my superannuation account which last year earned 8.1% all tax-free would make no sense. That amount very comfortably pays for a good health insurance policy