Lick 3 only has 3 notes (4 counting the bent note) from the major blues box. Two of the notes are in box 3 of the minor pentatonic, and the half step bend is also in box 3 minor pentatonic. So with a half step bend, you're making it sound minor which works over the 4 and 5.
If you don't bend that note, or give it a full step bend it remains major, therefore only to be used over the 1.