Cut 1 lemon into wedges and reserve. Zest and juice the remaining 2 lemons. In a baking dish, add 1/3 cup of the wine and the rabbit. Add the garlic, sage and half of the lemon zest and juice. Drizzle with olive oil and season with salt and pepper. Mix together so the rabbit is covered in the marinade. Cover with aluminum foil and marinate for 1 hour.
In a medium bowl, whisk together the flour, egg yolks, remaining lemon zest, a pinch of salt and pepper and 1 cup of cold water. (Reserve the remaining lemon juice for another use.) While mixing with a wooden spoon, add the red pepper flakes, parsley and the remaining 1/3 cup wine and stir together until combined but not perfectly smooth. The batter will be thick. Rest the batter for 1 hour.
When ready to cook, add the egg whites to a large bowl and beat with an electric hand mixer until light and fluffy. Sprinkle with salt, and continue beating until stiff peaks form. Fold the stiff egg whites into the batter.
Add enough oil to fill a large heavy skillet halfway up the sides and heat to 350 degrees F. Add the rabbit to the batter in batches, turning to coat and letting the excess drip off. The batter will be very thick. Add the rabbit to the hot oil and fry until golden brown and an instant-read thermometer registers 165 degrees F when inserted into the thickest part of a thigh, about 12 minutes per side. Remove the rabbit to a brown paper bag-lined sheet tray to drain. Cool 5 minutes before serving.
Serve with the lemon wedges on brown paper.