The main difference is in mixing meat and dairy. The Karaite tax boil a calf in its mothers milk to be literal, so the strict separation of meat and dairy utensils is not required. This is an area which makes Kosher eating, and living very expensive for many.
Yes, you’re correct on that, though I’d give them some leeway and define it as plain meaning and not literal.
What I referred to was what’s considered a kosher slaughter for consumption — there’s really no difference between the two that I can tell so I don’t understand the hechsher controversy.