Loki vs. Zoro
Remember that before defeating King, Zoro was weaker but still managed to hold his own against Kaidou for a short time. After defeating King, Zoro's strength increased significantly, that would allow him to hold off Kaidou for several minutes, similar to Yamato. This suggests that Zoro is likely near Yamato's level, making him roughly equal to or slightly below Loki.
Zoro could potentially handle this fight alone without Luffy's help. However, I assume Loki's abilities are related to thunder, which would give Luffy a natural advantage. Given Luffy's ability to travel within lightning regardless of Loki’s speed, he would ultimately be the faster combatant.
I think the fight will be interrupted by the holy knights.