He used conquerors haki in chapter 1. Be real.
Lucci did have haki. He was hitting Luffy with blunt attacks and dealing significant damage. He wasn't just biting and scratching and hitting finger pistols, half the shit he did including his ultimate attack was punching. Do things need to be spelled out with a narrator? You know how this stuff works. Luffy is established that blunt attacks can't hurt him. Lucci hurt him with blunt attacks. It's sure as shit not "fist of love."
Crocodile I think I've made a bunch of posts about this subject before, if not a thread. There's a scene in Alabasta where Crocodile thinks that Luffy has armament haki because he gets grabbed, and looks shocked and upset and has a sweat drop in the panel. Then after he gets pulled in and hit, he sees that Luffy is just using a tank of water and starts laughing at him. It has been established in the series that the strength of haki (as a power system) is directly proportionate to the strength of will (as in fighting spirit or dreams or whatever) of the haki user, and that losing your dreams or your will directly affects your power levels. Whitebeard's family was being torn apart in Marineford, and there are scenes specifically showing Whitebeard fail to use armament haki to hit the admirals in their logia form (kuzan even says "don't be ridiculous" when fodder goes "HE HIT HIM WITH PURE HAKI!!"), observation haki to tell Squard is behind him (this is a man who could defend from attacks in his sleep), conqueror's haki when trying to stop the execution (Luffy picks up the slack). This isn't because he's sick, it's because his entire life is his family, and he's failing to prevent his son from being taken away from him while his entire family goes to war and risks death for him too. He's losing everything and he knows it. Crocodile was utterly destroyed by Whitebeard (so he had haki to beat logias in the past) and his dreams were crushed, so he fell back to Paradise to be a small time casino and organized crime boss when he really dreamed of being Pirate King (as we learn in the Baroque Works cover story). By the time Crocodile returns to the story after regaining his dreams in that cover story, he's clashing with admirals and Mihawk and shrugging off Akainu's lava.
Blackbeard's entire Logia gimmick, that he EXPLAINS DURING THAT FIGHT, is that he still gets hit no matter what, because he's not that kind of logia, and darkness absorbs everything, even the inflicted pain. He goes on to say that because of his logia, he even feels MORE pain than usual, because of the unique qualities of the devil fruit, but he still thinks it's worth it because it's so powerful and special. When he says he hasn't been hit in a while, it is obviously not because he's a logia, it's because he is a very skilled fighter even without his devil fruits.
Blackbeard talking about Luffy's haki is the correct translation. You can prove this because Blackbeard references this dialogue later in Impel Down, the next time they meet.
"I thought 30 million was a little too low judging by his haki"
"Your haki is stronger than before."
