Newspaper Usage-Syntax

I know newspapers use short syntax to get attention of the readers but can we use the bold form is it grammaticaly correct?

And in the 4th example normally does it need 'about' after 'backs off' and an s for Obama's birth claim ?

1.Hillary Clinton to return to campaign trail Thursday

2.Barack Obama, Bill Clinton To Fill In For Hillary Clinton

3.Hillary Clinton to Address Millennial Voters During Campaign Event
in Philadelphia

4.Trump finally backs off Obama birth claim