Danika, Was it your expectation that the family would eat all of the cookies you provided? I'm like WillyNilly, Christmas treats are to be shared with friends. Regifting would be if she took your cookies, packed them up as individual party favors and handed them out to the guests to take home.
My thoughts exactly--especially with foil-wrapped toffees.
I would not have considered this regifting, and if I were having a party and still had toffee in the house, there's no way I wouldn't offer it to my guests.
And w/ the toffees, I would assume that *you* liked those toffees yourself, and that I could offer you a chance to eat some.
(I think it might be safe to assume that Becky's family liked cookies A and B enough to eat all of them, but that doesn't mean she rejected the other cookies. And I know my *own* reaction would be to make Becky's stash next year bee all cookies A and B, since it seems she likes them so much.)