Do not trust KLM`s website in terms of finding available seats, call the Helpdesk, I have made several tests "Internet vs Phone " and the agent always found empty seats, the internet did not.

You need 7500 FD Points for every flight number, if you find a PHL-HNL connection with only one flight number, your chances are good to get a FC seat, but not in Coach.

Based on my experience FC seats are much easier to get than Coach, especially on US Domestic Flights.