Congrats to your daughter! My DH proposed to me at POR. He had ordered a flower arrangement from Disney Floral and requested it be delivered to the room after 5pm, so it would be there after we got back from the parks and that's when he'd propose. Lo and behold, the arrangement was delivered sometime between 9am-1pm and was there when we came back for our mid-day break. He wasn't expecting it and had to scramble to grab the ring out of the dresser and propose while I stood there confused as to why there were flowers in the room. LOL! Its a good story now I guess, but he was upset about it at the time. The moral of the story is do NOT trust Disney Floral with time requests. You mention you want something delivered in the evening but perhaps the next day would be better.
Fast forward a couple years later, and DH had a flower arrangement delivered to our room at POR for our first wedding anniversary. They were delivered sometime between 9am-1pm again (which was fine this time lol). So I think they tend to come early in the day.