If its behind closed doors why not grab a few of the young Handy players and do what the league is advertised to do (make All Whites). Leave the MLS players as they are trying to fight it out bring maybe a few European based players. Its only Canada and some of them should be reasonably fit at this time of the year and would hopefully challenge the NZ Prem players to lift their game to another level and bring that experience back to National League.
Your idea has merit and agree to a point, but only if done also with a plan, that would be looking to promote any young guys - from the amateur Handy - in front of European football scouts, ie try to help them get a pro gig overseas. Andre de Jong is yes one player comes to mind. Maybe Heraf has that in mind for this AWs camp, as he has been involved in something a bit similar with the Future Football Ferns Programme, and that’s had success getting some younger Ferns pro gigs.
However the Handy players would mostly be already, being watched regularly in NZ, by NZF staffers. I'm talking more about bringing into this AWs camp young guys like Mitchell who have been overseas for a 1-2 years, and may not have been viewed up close for awhile, ie what level are they at now.
I think you should be in a pro club environment first, to make the AWs - even a downgraded wider training camp - like I'm hoping this March window will be.