So before I get into anything, keep in mind that when I made the "you're not being the game dev" comment, it wasn't meant to imply insult or anything. I'm just trying to ensure you understand the issue.

As for the game, let me give a more practical example. Let's say you were making a tabletop RPG instead of a LARP game. Tthe things the player needs to play your game and your pre-made campaign (not including things they need to bring such as dice) are the PHB, the Dungeon Master's Guide (DMG), character sheets (so players can know how stats work) and a full write up for the pre-made campaign so the DM knows how the story plays out. The PHB, the DMG and the pre-made campaign scenario are all things the player needs to play the game as intended. They provide the rules. They provide the setting. They provide everything that defines it as a game. What you posted for this would be the equivalent of a few pieces of artwork from the Player's Handbook (PHB) and a poem that is part of the pre-made campaign but doesn't help define much of anything.

Lastly, when I bring up about special clothes and people it's because LARPing involves a lot of people to do it right and the right outfits to set the mood. Think about war reenactments. Those are a form of LARPing, and they take lots of people to do right.

That all said... no, I've never heard of any "symbolic meaning" to a white crow. In fact, I didn't even know white crows were an actual thing until I looked it up 30 seconds before I wrote this line. And that's an important thing to also consider: when making a game, you need to teach the player how to play the game. That includes teaching them any important symbolism that matters for it in case they don't have experience with it. After all, everyone's cultures are different and what's big and important to one culture may not mean anything in another.