Thanks for your reply, and for the suggestion about days 31-44. I don't remember feeling particularly sick from anything after my other Whole30's, but then again I never used Day 31 as an opportunity to binge either. Given what I'll be eating at the reception, some bread-type stuff the week before might be smart just in case.
As for whether to take BC just to re-schedule my period, well, I'll see how October goes. If I'm still "on track" for November 21/22 then I'll consider it.