You are wrong, because you can't reorder the letters:

anothertest
 |||   |||| -> nottest
 not  atest 

With that definition it means not and test can have some other letters in the middle like in this case a in the second string or her in the first one.

Well yes, it says what the 2nd argument means, and that its orientation goes from top-left. It doesn't actually say that it will always be (0, 0), otherwise why even pass this argument?

the returned string should only contain lowercase letters

Actually there is no blank test, it's just that the tests don't use the correct template so it displays like an empty group. This should be fixed when someone does the update to the new framework.

No answer, no issue.

Please provide sufficient information (language).

No, the numbers are after all the letters.

P->Q->R->S->7