So, I’ve seen two ways Spartan has been written when referring to the Spartans themselves in the books. One way is SPARTAN, it’s less common it seems but, if I remember correctly, it’s how it was used in the first couple of books. The other way is just Spartan. Looking on Halopedia, it says SPARTAN is when referring to the program as a whole and Spartan when referring to the supersoldiers themselves, but that doesn’t seem to be the case.
It’s not an acronym, so there’s no real need to capitalize the whole word. As such, there’s nothing wrong about only capitalizing the first letter of the word.
as you’ve stated, the wiki shows it as SPARTAN is the program, and Spartan refers to the individual. and that does seem to be the case with the official books.
In most cases, yes, but I remember the original Fall of Reach wrote it as SPARTAN on the book summary and a couple of times in the book. Might not be the case with the reprint though.
I honestly don’t think it really matters as when taking about the program you could just write “Spartan program” and it’d achieve the same thing, and if you’re talking about the soldier, you could say “Spartan-[insert Spartan tag]”
Main reason I’m asking is because I’m big into the lore and noticed it was spelled in all caps in one of the books I read. It’s just one of things I feel I need to know for whatever reason lol