Hidan is reachable for semi-FTP players. I'm a medal/pass only player and finished him on this event for coupons, no direct cash involved. If you're 100% FTP it would be a huge challenge and you'd need to plunder 3X every single day but it's possible in theory. I didn't bother going for him with any of my free alts because when coupons are that scarce you're better off just grabbing power. 4k for something like a kimono when you don't plunder or have monthly pass is like a 3 month investment.