This isn't really Elimination. This is Hunger games. If we voted who gets killed, then it would be Hunger games Elimination.
As for the Cornicopia, If you don't go, it's too unlikely that you'll win. So most people will go, and only half the players will be left for day 2. Instead, have one person killed per Item gained by another player. (EDIT:) Have Day one be the Only time you can start a PM Alliance with someone. If you go for an Item, you can't Ally with Someone. If you don't, you can talk to up to two people!
24 Players: No. That just doesn't work, there will be too many, or too little. Instead, just have the same amount of Districts as half of the Players, if there's a District without a Player, then it's assumed that their partner died in the Bloodbath, ensuring they get an Item. Also make it so that you can't kill your district buddy until day 4 or so. Or until there's half of the players remaining.
Star Crossed Lovers: They count as one person, with two actions. so a defense action protects both of them. This allows them to attack and defend. But if one Dies, the Other nightlocks themselves. If they're the last two remaining, they suffer a bitter, bitter breakup, probably with Insults and Screaming, and go into Endgame. Or they automatically start with Nightlock.
Endgame: Whoever has the most Successful Kills/Defenses gets a (What are the Parachute things called?) and kills the Other, With a Shotgun. Or, They each Get 3 new Weapons. A Rock (Rock), a Net (Paper), and a Shotgun (Scissors). The Rock can destroy the Other's Shotgun, and then Kill them, the Net trapps the Person with the Rock, and kills them. The Shotgun Kills the Person with the Net.