I mixed all filling ingredients for shaker lemon pie to sit overnight instead of just the sugar and lemon. Is it ruined?

Thank you Lori T! It did in fact come out fine. And I did refrigerate the filling overnight as well, fortunately.

I doubt it, providing that your filling sat in the refrigerator overnight and not on the counter. The acidity of the lemon juice might have firmed up your eggs a bit, but it should not have hurt anything. The only way to know how it affected things would be to bake the pie as usual. Let the rest of us know how it goes, since your experience might lead us all to repeat the "accident" in favor of a better pie. It's not ruined, it's safe to eat, and experiments do sometimes have happy endings.