True, even if Malakaus went with the whole "Make them from blade molds", it'll take a lot of time just to hone the molds into an edge, and I don't know how many other crewmen would have the knowledge of how to not sunder glass blades with poor sharpening. More so if Malakaus has to do it alone. Now if there is a long run, that's a bit more finicky. Malakaus has a lot to do in the long run, and making the glass into weapons or armor isn't one of them. The Boomsticks would be easier, if much more experimental. Maybe I could instead use the glass as bullet materials. Light, sharp, Malakaus would just need to figure out how to turn them into the right kind of bullet. If Moonstone and Malachite handle the shock and heat better than steel, Malakaus might actually have the materials to make a decent boomstick.
Eh... I wouldn't make a katana out of malachite. Katanas are too delicate to use such a light metal. Malakaus would need heavier, sturdier materials to ensure that the blades don't chip and dull after each battle. And even than, Malakaus is making weapons that could be used haphazardly and without too much training. Katanas are finicky weapons that require a lot of training to use more than a simple hack-and-slashing weapon. Even Malakaus doesn't use his Wakizashi for more than precise stabbing motions to ensure that he doesn't break the blade trying to bash it against someone else weapon or armor bits. He's going for practical, mass produced stuff over exotic weapon proficiency.
That being said, how much time would Malakaus have to make these weapons, and how urgently would Sharee need them? If He's expected to get them ready by the time they attack the slave ship, which if I may venture a guess would be within a day or two, Malakaus won't even bother to forge them into swords and either wait until they stay on shore long enough for him to make a full set of armor (Since the ship lacks a full forge as far as I know) or carefully chip pieces off and make Macuahuitl instead. Swords are nice, but as far as practically goes it's easier to make spiked clubs. If Sharee doesn't feel that it's particularly urgent for Malakaus to make the crew any more weapons and no one actually wants glass armor, than he'll instead focus on using the materials for his boomsticks.