I had baked and decorated a bunch of vanilla and red velvet cupcakes with buttercream frosting yesterday thinking it was for today, but its not due till tomorrow. Will it be ok till then? What should I do to keep it as fresh and pretty till then? Thank you

Well cupcakes dry out faster than cake but it also depends a bit where you are (climate) and your recipe.

I would probably freeze them until pick up/delivery (they defrost quickly here). 

But if you have a nice "wet" filling or were brushed with syrup they could survive another day in a cool room like a cellar  (that I don't have lol). I find anyway freezing keeps stuff the freshest. Why have it linger around on your counter when it can chill for a while?

Will it be ok to freeze with fondant decorations on it?

Yes. Place them in a box and wrap the box in cling film. Do not unwrap till thawed so the condensation will stay on the outside (on the cling film and not effect the cupcakes.

Ok next time I will give that a try thank you so much for your help!