This is all very familiar with this North Eastern American English speaker except the "quite good" one. The rest seem normal to me in my American English. Perhaps it's too many Dr Who and or Monty python as a youth. Though in New England the language can be very sarcastic and indirect.
Really? I read the same sentence (as an American) and immediately thought that they must be referring to British English. Certainly nobody says brilliant as an affirmation here.
And "no problem" and "not bad" are both common colloquial statements in American English.
This piece seems to be very much about American English, when I read something like:
> In English, this feels bizarre. If something is good, you say: Nice Great Perfect Brilliant