The other Asgardians would be in shock. Heimdall, for instance, would immediately sense that something was wrong with Thor. He might try to find a way to break the spell himself or inform the other powerful Asgardians. Odin would be furious with Loki and demand that he unfreeze Thor. The Warriors Three - Fandral, Hogun, and Volstagg - would likely want to take immediate action against Loki. They might try to fight him to force him to reverse the spell.
Other characters would have diverse reactions. Jane Foster, if she's aware of what's happened, would be desperate to save Thor. She might try to use her scientific knowledge combined with any magical knowledge she's picked up in her time in Asgard. The Hulk, if he's around, would be confused at first. But once he realizes Thor is in trouble, he might smash his way through anything to get to Loki and demand that he unfreeze Thor. And the other minor Asgardian characters would be filled with fear and uncertainty. They would look to their leaders for guidance, but with Thor frozen and Loki in an unpredictable state, they would be in a state of chaos.
Well, perhaps Loki freezes Thor as part of a deal with an enemy. Thor is frozen and the enemy thinks they can now easily take over Asgard. But Loki has a hidden agenda. He freezes Thor not to harm him but to protect him from a more dangerous plot. Thor, while frozen, has visions or dreams that give him some new power or knowledge. When Loki finally unfreezes him, Thor is stronger and together they outwit the enemy and Loki's true loyalty is revealed to Thor, strengthening their bond.
The people of Arendelle would be in a state of chaos and mourning. Elsa has been their queen and their protector. Some might be afraid that without Elsa, the kingdom would be vulnerable to new threats. The trolls, who have known Elsa since she was a child, would also be deeply saddened. They might try to find a way to bring her back, using their own magic and knowledge. Sven, Kristoff's reindeer, would sense the change in Kristoff's mood and would be more subdued, staying close to his owner during this difficult time.
Thor would be furious. He would immediately start looking for Jane, using all his resources. He might first try to reason with Loki, but if that doesn't work, he would not hesitate to use force.
Thor could also become very angry. Not at Loki, but at whatever or whoever caused those scars. He might vow to avenge Loki and seek out those responsible. For example, if the scars were from a battle with a particular enemy, Thor would be determined to confront that foe.
Loki's relationship with Thor would be filled with mixed emotions. He could be resentful at first for getting into this situation, but as time goes on, he might come to rely on Thor more. They would have to communicate more openly about their feelings and fears, which could strengthen their bond in a different way than before.
There's 'Thor's Redemption in Loki's Arms'. In this story, Thor realizes his true feelings for Loki after a series of events that nearly tear Asgard apart. It's a tale full of emotion and character development.
Olaf would try to make Anna laugh. He would tell his silly jokes and do his goofy dances. He would also try to keep Anna warm with his carrot nose. He might even build a small snowman inside the room to keep Anna company when everyone else is busy.
Loki might develop by becoming more honest with Thor. For example, he could finally admit his true feelings and intentions from past events. This would be a big step in his character growth.
I really like 'A Different Path for Loki'. In this fanfiction, Loki is given a chance to redeem himself in a unique way. It's full of interesting plot twists and great dialogue between Thor and Loki. The author does a wonderful job of exploring Loki's psyche and his relationship with Thor against the backdrop of the Asgardian world.
If Loki survived in Infinity War fanfiction, it could have led to a very different outcome. He might have used his trickery to deceive Thanos in some way. Maybe he could have pretended to be on Thanos' side while actually working against him. This would have added an extra layer of intrigue to the story as the other characters would have been unsure of his true motives.