@Anne Shaw, regarding the journal entries, and whether or not Marshall’s voice is consistent with his character, we all have different voices when we speak, think, or write, especially when we are aware that our words will be viewed by others. We are always aware of our audience and code-switch even within the different mediums. Also, we are talking about a different Marshall after the passage of eleven years.
This is just my observation, but when we are looking at a finished product, like the journal entries, we need to infer the thought process and intent at the time of its creation. I would like to be in the room as Marshall is mulling over his entry--I can imagine him bouncing his ideas off of Toby, who is obviously his most trusted friend. This interaction would provide the reader with insight into their relationship.