Is there any additional difference between everybody and everyone apart from that everybody is less formal than everyone? What about somebody and someone? Thank you in advance.
Fandorineverybody is less formal than everyone

Some people say so, but I don't perceive it that way.

The "everyone"/"everybody" distinction (if any) is is an old chestnut -- as is "someone"/"somebody", "anyone"/"anybody" and "no one"/"nobody". If you search Google you will find lots of discussion. To me, the words are freely interchangeable as far as I can tell, though it's impossible to bring to mind every circumstance in which I might use them, so there remains a chance that I might have a slight idiomatic preferences in certain situations.
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My dear friend, There is no difference between those words.
Hi Mr. Wordy.
Mr Wordy To me, the words are freely interchangeable
That's what I want to hear. Emotion: smile Thank you a lot.

To Anon. Thank you for an answer.