Two
no no no it's one wherever. If you're going to use it as two it's very old fashioned and can only be used in questions. (Where ever have you been?)
Whoever is one word and is pronounced like "hoo ever."
It's forever after
Generally, it's one word.
One is two words and the other is one. Their meaning is the same: eternal.
two.
Two words - "one day".
No, "ever" and "dance" do not rhyme. Rhyming words have similar ending sounds and these two words have different sounds at the end.
I can find no evidence to support it ever being correctly written as one word so at the present time it should be written as two. These things can change though many words that were once two were formed as one because of usage. Sometimes one of the words is even shortened as in "Alright".
They are two words conjoined to be one.
It is two words. Writing it as one is acceptable in the UK and is referred to as a "Britishism." But in American grammar, it is always two separate words.
two
"After school" is typically written as two words.