2A

‘But I’m near you. I could reach out and touch you. I could even make you bleed’ Do you think the writer was threatening, or trying to threaten, Neil? Why?

I don’t feel this is threatening language. The writer sounds more obsessed by the subject of the monks than by wanting to hurt Neil.
IMO, “I’m near you” means physically. I’m looking for someone on the dig to be the author of the letters, and this includes Neil’s assistants, one of whom we’ve not met yet.

The letter is rather threatening mentioning the fact that they could even make him bleed.

If I received a similar letter I would consider it threatening and have serious concerns.

While seeming to feel a compulsion to tell all that he/she knows about the monastery the writer is also threatening Neil and his unease is quite understandable.

I don’t think it was necessarily meant to be threatening but that is how it came across.