A long time ago I made up a filling by boiling orange juice and corn starch until thickened (about 1 cup juice with 4tbsp corn starch). It was delicious and a little tangy which made a perfect cake filling for an "orange creamsicle" type cake (in my opinion). I used orange cake and vanilla cake (swirled).

I refrigerated that cake with the orange juice filling, but now I want to make a cake with this filling for my sister's bridal shower and I want to use fondant and I don't want to refrigerate the cake.

Do you think it would hold up okay if I fill the cake and decorate it the day before the shower without refrigerating it overnight?

Also, I used cream cheese frosting last time but I want to use regular buttercream for the shower cake so I don't have to worry about it melting. Does anyone have any buttercream flavoring suggestions that would go well with an orange creamsicle cake? I just bought creme bouquet because I heard it was good but I have no idea what it tastes like yet. Would it work?

Thanks for your comments and suggestions!

Creamsicles are vanilla and orange swirls, if I remember correctly. So I guess either of those would work.