I am doing a few dozen cupcakes for a Tuesday night baby shower. Half chocolate, half white, all with a "buttercream" (not a cooked BC, just a butter + Sugar + Vanilla recipe)

Because of my schedule I will have to make all of the cupcakes on Sunday, and ice on Monday night (or at the crack of dawn Tues morning). A friend will be picking them up Tuesday afternoon (I'll be at work, he's picking them up at our house) for the Tuesday night party.

Should I keep the unfrosted cupcakes in an airtight container Sun night, then just keep the frosted ones in a bakery box from decorating until pickup? I don't want them to dry out in that 12-18 hours, but I can't really think of another option.
Should I refrigerate?

Thank you!

You definitely want to keep the unfrosted cupcakes in a tupperware container.

Can you fill the cupcakes with buttercream? That would help a little bit.

I've always just left my unfrosted ones out with some plastic covering them and then boxed my frosted ones and left them out too...never have had a problem with drying out