Fill a large pot with water. Scrape in the seeds from the vanilla beans; add the beans. Bring the water to a boil. Working with one lobster at a time, submerge the lobsters headfirst into the boiling water, and cook until the shells are bright red and the meat is opaque, about 5-6 minutes. Using tongs, transfer the lobsters to a large bowl; cool. Remove the meat from the tails and claws. Cover and refrigerate until cold.
Whisk the vanilla bean seeds, vinegar, lemon juice and honey in a large bowl to blend. Gradually add the oil, whisking until the vinaigrette is well blended. Season to taste with fleur de sel and pepper.
Using a melon baller, scoop out the flesh of each fruit to form small balls.
DO AHEAD: The lobsters and vinaigrette can be prepared up to 8 hours ahead. Keep the lobsters refrigerated. Cover and refrigerate the vinaigrette; bring it to room temperature