Strinsinger-
I agree with "A folk song has to be sung by those who are outside the music business genre.A popular song can cross over. " as at least a portion of a definition of "folk" or "trad". Necessary, but not sufficient. In your list, though, only 2,3,4,5 and 10 were really "pop" songs.
Parenthetically, 7 (Johnny I hardly knew ye) was not of Irish origin.