Please note my changes and underlining above. I don't know what you mean by the underlined part. Are you asking us how common sentence #2 is?
Sentence #1 is an old-fashioned way of saying "I am surprised that somebody came".
Sentence #2 is grammatically OK but not very natural. I would expect to see "I wonder if anybody came". That would be used of an event or a situation that I didn't attend and I am wondering if anyone else actually turned up.