Here are my edits:
Lunch -
Cabane de L'Isle - only do this one if you plan to use their beach lounges after lunch. With the chairs, the lunch is probably worth it, but without, it's well overpriced for what you get. (disclaimer - it's been a couple years since I've eaten here, but we took it off our last based on our last very expensive and unremarkable meal)
Sandbar - great view, but you don't get to use their beach chairs unless you pony up an extra 70(?) euro each. The food is sort of ordinary and certainly not worth the price, but you're paying for the view.
Gloriette - a keeper for sure. Mellow, local vibe. Good food, great prices.
Shelloma - brand new. You may be the first to eat there. I'd skip it in favor of something else. (I'm not really a huge fan of Shell Beach - - very small and not as pretty as three places above, or the ones below)
Nikki - beautiful view and very good food (better than you'd expect). It's a very similar view to what you get at the Sandbar. If I had to do one or the other, I'd do Nikki...........better food.
La Plage - Never eaten there. I've always been a little turned off by the look of the dining room. Maybe the view is great looking out from the tables, but when I look in from the beach, it doesn't look inviting. Lots of people love this place so take my semi-uninformed opinion with a grain of salt.
Consider adding:
Santa Fe - Great food, fantastic view, just up the road from the beach. (we went twice for lunch in Dec)
Tamarin - beautiful garden (of Eden) setting. Truly a tropical oasis. A favorite of many on the forum.
Dinner (a lot of my commentary may sound harsh, so apply grains of salt as needed).
La Casa de L'Isle - Skip it. Too expensive for unremarkable food and no view at night
Bagatelle - I've never been and have little desire to go. It turns into a dance/party place at night which is not my scene at all. I'm not looking to see and be seen.
On the Rocks - Skip it. Way too expensive for way too unremarkable food and no view at night. My wife and I have been wanting and trying to go here for years, but every time we look at the menu, we get bored at the options and outraged at the prices. Half the time, we can't even find anything we really want to order! They have a cocktail hour starting at 5 pm. That might be worth doing as it will still be light out at 5.
Bonito - never been, so no comment
Aux Amis - Skip it. Too expensive for unremarkable food and no view at night. That's a little unfair on my part as I've never been at night (!), but we had a lunch there that was fine although unremarkable and certainly not rave-worthy. It's a beautiful place and the staff is great, but the food is the weak link. It's a better lunchtime option as you can use their chairs and pool after you eat.
Santa Fe - Definitely, although if you only have one meal to devote to Santa Fe, I'd do lunch
Francois Plantation - you may be the first to dine here. Very expensive. I'm turned off to the place based on their prices.
Consider adding:
Cote Port - my new favorite place
Eddys - unique setting and loved by many
Orega - a new place that is loved by nearly everyone (except me.........but it was a fluke of bad service not a systemic problem)
L'Esprit - very gourmet, but very worth it. They charge prices similar to some of the places you list (on the rocks) but, here, the food lives up to the price.
Gloriette - a different menu at night. Great pizzas[/QUOTE
We've never been to Shelloma, because it is new this year. It has nice sunset views, but I can't comment on the new food.
I love Grain de Sel (only been there for lunch) I think they have the best frites on the island. The salads are really good too. And a decent wine list at decent prices.
Since you are staying at Cheval Blanc, you may not need the advantage of the beach chairs at lunch, but I like eating lunch with my feet in the sand, so I like lunch there. I agree that there is no view at night, so I don't know about dinner there (I think you can get drinks and appetizers during the weekly fashion show).
I am plus/minus about Bonito. When we tried to go for sunset drinks a year ago, they weren't open. Another time, we had awesome sushi from a guest chef.
Never been to Bagatelle because of its reputation as a party place (which we go next door to Baz Bar for, eating some place else beforehand, because they mostly have sushi for food. I know, I just commented about the guest chef sushi at Bonito, but generally speaking, sushi is not my go to food).
We have never been to Cote Port, but might consider it next visit because of Pascal.
Hope you have safe travels!