So then Cracker's Haki = Luffy's Haki = Doffy's Haki. And if Doffy breaks through his own Haki grabbing a non hakified sword, it just means Doffy's Haki has been so damn strong. Doffy's grab breaking through Cracker's Haki confirmed.
Honey Pretzel is a thrust. While Cracker's real sword is much better at cutting than the biscuit sword, as for thrusting, there shouldn't be a difference, because all that matters is how pointy the weapon is. Especially when hardened with Haki.