Hi Jill!
According to the Disney website, Chef Remy is still making appearances at
Les Chefs de France in the France pavilion at Epcot.
I have not seen anything to suggest he will not still be making appearances in August, but characters are always subject to change.
I cannot think of any other dining experiences with surprises such as this, but the character dining always adds a surprise element as the characters will always interact differently, and turn their hand to each occasion.
One character dining experience that sticks in my mind as being a little unusual is the
The Garden Grill Restaurant at Epcot, as this restaurants rotates very slowly throughout the meal. You can barely notice the movement, apart from the fact the scenery changes!