I'm hosting a bridal shower/sit-down tea for a friend this coming Saturday. The RSVP date was this past Saturday. Of the 30 people invited, only half the people responded.

I emailed reminders on Sunday and have had all but 3 people respond. (May I say that I much prefer the late responders who are apologetic and gracious enough to ask whether they can still come.) At this point, I want to finalize the headcount.
Is it better to email the last 3 and say "It looks like things are busy for you right now. We'll miss you at the shower, but I hope to see you soon." (We are all friends of varying levels of closeness.) Or should I wait to see whether they respond "yes" and then say "no" as nicely as possible?
For fun, here is the menu:
Course 1
- Gingersnaps with lemon curd
- Banana muffins topped with coconut jam and crushed candied lime peel
- Carrot – pineapple – raisin muffins (made with honey – so moist)
- Orange scones with clotted cream
- Seasonal fruit
Course 2
- Chevre and herbes de provence scones spread with herbed goat cheese
- Cucumber sandwiches
- Chicken almond sandwiches
- Homemade pickles
- Fingerfood veggies
Course 3
- red velvet mini cakes
- shortbread dipped in chocolate
- Moment to Myself Cheesecake (molten chocolate middle)
All with a Tiger Hill Estate Nilgiri Tea, milk, cream, sugar, splenda, vanilla sugar