: And Hood making his dramatic announcement that "he's the one who caused
: them to go missing" or something to that effect. So I dunno if he's referring
: to a coverup after the fact, or just sending them on their mission to Harvest,
: or what (it was Cutter's idea to go on the goose chase that led to the Shield
: World.)

I assumed Hood was in charge of rescuing the ship and later determined that she was "lost with all hands" for whatever reason, be it a cover-up or otherwise.

: Come to think of it, how much do we actually know about Hood's service? I
: guess I didn't realize he could be an admiral back then, since the first
: we really heard about him was First Strike and from Halopedia his birth
: date is 2490, which means he would have been fairly young at the time.

He'd be about 41 years old and 20 years in-service during the Harvest Campaign and would probably be a commander, captain, or maybe even a rear admiral if he played his cards right. All of these ranks would grant him access with the highest levels of the Navy, especially considering his family background and likely connections.