This post reads as a DYN...IA, was that the intention? You really have to learn to relax more, after all you catch more flies with honey than lemons. I would save you angst for when you need it the most, that is when everything goes to custard and you have to get somewhere and need all the help you can get.

I would guess that under the old system QF may well have been able to easily check guests in for Air Vanuatu but under the new system it sounds like it is not so easy. Likewise previously you may have been able to board as a QF Gold in Y down the business class line but perhaps Air Vanuatu complained to QF about service delivery and this has been halted (and just the sign has not been changed)?

Really though, does it matter? What would have been the issue checking in at the correct counter and boarding using the economy line? It is all for the same plane ! Once you are onboard you are just another Y class PAX, just like every other Y class PAX.