There is no supercharger site on Lānaʻi. I did see some 2nd gen WC in that area where all of the Teslas were parked. I don't think Lānaʻi needs a SC site, to be honest. It's only 9 miles from the Manele Small Boat Harbor to the Sensei Lānaʻi, and a long range vehicle could do that trip 20-30 times without needing a charge. And furthermore, it's not going to be doing that journey all night long, because no ferries run at that time, so the 2nd gen WC can recharge those cars at that time.
If there's an island that needs a supercharger, it's Hawaiʻi Island. Put one in Hilo and another in the Kona area.