First, if the insects have been bothering plants, they are not fruit flies but fungus gnats. Two entirely different insects with different life cycles and methods of control.

A potting medium and water regime that attracts fungus gnats is not going to be at all encouraging to the growing of succulents. Succs want very durable potting soil with very fast drainage and minimal water retention. And not to be growing in a glass container without a drain hole!! Repot in a proper succulent soil and there will be no issue with any fungus gnats and no need to to use sand to deter egg laying.

Fruit flies are not interested in plants - they want fruit :-) Keep any fruit in the refrigerator. The vinegar or wine traps work well for fruit flies but they will have no effect on fungus gnats.

If fungus gnats are still a problem I would suggest purchasing gnat nix! Works well if you cover the soil with a thin layer. But also would suggest repotting or watering much less to prevent the succulents from rotting.