If more information was presented on the popup for appts (and maybe only completed ones) then you wouldnt even have to go to the order to review for certain things.

I would add a line item price next to each name (so one new column) and then show the gratuity on completed orders. Then you could quicky review a whole days orders without actually having to leave the calendar or frnot desk view.

Another option would be having the "view order" go to a slide out, always on top screen like the new appointments/checkout. And i would reiterate my suggestion to make the edit appointment work that way as well.