Creator of images

The Spiral is the fear of your mind lying to you, an aspect which is very much present in the original Herobrine creepypasta- OP explains that they would "constantly think [they] saw the other player" but could not manage to see him proper, bar their first encounter. The key takeaway here being that they thought that they saw somebody else in the fog, but could never confirm it, which I imagine would create a sense of paranoia that their mind was playing tricks on them- perfect for the Spiral. Similarly, when OP apparently posted about their findings online, their messages were quickly deleted- the suppression of knowledge about the figure that they had encountered would create more unknowns for OP and further the paranoia, which is why Herobrine could be considered an avatar of the Spiral. The OP also seems confused about structures that appeared in their world, since clearly they could not generate naturally- if Herobrine was an avatar of the Spiral, it would make sense for him to build random structures throughout the world just for the purpose of confusing the player and getting into their head.

As for the Stranger, I think that there's less evidence that Herobrine should be categorised this way. The Stranger is the fear of the unknown and the uncanny. Even though now in 2024 pretty much everyone who has heard of Minecraft has also heard of Herobrine, in 2010 Minecraft was much more niche and not every nook and cranny of the game had been explored, and so back then, the concept that somehow a ghostlike figure had made it's way into the game wasn't impossible. His existence could genuinely be believed, though not fully understood, giving credence to him being an avatar for the Stranger. Backing this up is his appearance of being exactly the same to the player character, but slightly uncanny, having glowing white eyes- with a modified, unusual appearance being a telltale sign of the Stranger. But his behaviour doesn't really align with how you'd expect a Stranger avatar to act, since all he does is watch the player and (supposedly) stop telling them to find more information. Which is why I think he would be an avatar of the Eye.

Throughout the original creepypasta, Herobrine doesn't take any direct action to confront or communicate with the player; every time he's mentioned in-game, he's described as simply watching from afar. Although this creates a sense of paranoia for the OP, they are specifically paranoid of being watched by somebody, mentioning that they constantly tried to catch whoever was watching them- although to no avail. Herobrine's behaviour here also reminds me a lot of the way that Jon is described by his victims when he appears in their dreams, just watching silently, never interacting. What's more, the situation drives OP to post on the forums asking about this, but their post gets deleted. One of the key aspects in regards to the Eye's identity is the desire for knowledge, even if it comes at a cost; here, Herobrine's presence leads OP to repeatedly seek out answers, despite the fact that it caused their posts to be deleted and for them to get into trouble with a moderator. My last persuasion point is that Herobrine's one key iconic identifying feature is that he literally has Evil Scary Eyes.