Not sure how the exact operators plan, but usually there is the option, in lieu of an alternate, of carrying extra holding fuel up to 2 hours. Of course, the forecast has to be acceptable and probably better than the usual. I went there and we planned 2 hours of holding--weather was clear and breezy as it mostly is. In the USAF, we could do the same except for high latitudes and the Aleutians where we had to have an alternate, PAED usually.
Also, the Chilean CAA has a policy that only 1 aircraft can be operating between the ETPs from the mainland or to Tahiti. IOW, once inbound from Taihit and past the ETP, an aircraft cannot be released from Chile until the airborne has landed. Or, if you depart Easter Island for the mainland, the flight has to be past the ETP and committed to landing on the mainland before another flight will allowed airborne or past its ETP and committed to land at Easter Island. One t a time.