I've pre ordered gluten free lunch with no issues. You go over your order with the cashier when you pay so there's no to see a chef or manager.
A notice comes up on
MDE when your are able to preorder and I believe there is a button to view the allergy free menu. I can't remember from last year, but it's clearly marked. We will be doing lunch again in May and pre ordering again.
I'm not sure I'm following, but whoever makes the reservation is the one who's magic band is scanned at check in and "responsible" for the whole reservation. (I.e.: pays, makes changes to the ressie, preorders) Individual magic bands are not scanned for everyone in the party. I don't know how it works with the dining plan since we pay out of pocket.
When you view the menu to pre order for everyone, make note of the prices and just ask the additional two people for the money up front. When it comes time to pay, use your dining credits for your share and charge the additional amount to your magic band or pay cash. I don't do the dining plan, but maybe someone who does will comment if that will work.