I have no idea what Switzerland and Germany are doing in the first panel but it looks like fun.
The completely awesome apology card doesn’t belong to me! [link]
Israel didn’t say ‘nice’. He said ‘very nice’ [link]
Panel 4: In my headcanon Czechia knows some Slovak (also a bit of German but she has ambivalent feelings about that). She sucks at speaking it though and Slovakia always makes fun of her if she tries.
Forgot the stars on America's flag.
EDIT: Okay Israel did apologize today. Only took him 3 years.