Although this got averted by the time of Conviction and Blacklist, how exactly does Sam keep getting lucky enough to find enemies to interrogate that speak perfect English in the early games? Somehow I doubt a low-class, random Indonesian militant or a North Korean soldier stationed in some backwater base is going to know enough English to respond to Sam's inquiries.
There are only three Indonesians Sam interrogates: One of Sadono’s officers at the embassy, a technician in the submarine base and Sadono himself. It’s not a big stretch to find three English speaking people in a large guerrilla army with several hundred members.
This. These are the only interrogations you need to do - everything else is essentially non-canon.
It's also very possible some Translation Convention is going on, where Sam uses some of the native language where necessary.
How could Grímsdóttir, who was born in 1974, and therefore 7 to 15 during the Reagan administration, not know the phrase "win one for the Gipper"?
She's not the only kid/teenager I've heard of who just didn't care about politics growing up. Also, she seemed more of a bookworm than anything else (at least during Chaos Theory), so that makes it even more likely she wouldn't know Reagan's slogans.
We all know Sam officially does not exist. So where does that leave Sarah re Education, Social Security et al, particularly after her mother's death? Does she too not exist? Is she officially a ward of the state with two deceased parents as cover? Sure she is an active member of society by the time of the games, but how well does her history stand up to scrunity (and by extension how much of a threat to Sam is it if the truth ever got out)?
Novels:
The first novel has real-life weapons designer Gerald Bull as a Posthumous Character and includes details about his assassination and work that show the author did research— so why is his name misspelled as "Gerard" every time it appears?
It might be a Captain Ersatz even less disguised than normal.
as a Posthumous Character and includes details about his assassination and work that show the author did research— so why is his name misspelled as "Gerard" every time it appears?