I missed something in the plot?
My guess is that they went to Red Lobster to pick up a wagon load of crab crackers and bibs
The event today did mention the Lionguard testing out new weapons and most camps on the new islands have a box of weapons for players to try out.
The event leading up to the island opening up was another raid near the Clawrl Island Portage Waypoint. In this event, players coated their weapons with a special solvent which pretty much caused their weapons to carve the karka like butter. If you go to the new map and check out the landing camps, you’ll find solvent guns and stuff which contain the special Lionguard Solvent used during the event.
My guess is that it’s just assumed that your weapons are coated with this solvent already/while in karka land.
Men of Science [MoS] – Tarnished Coast
The solution to the karkas’ impenetrable shell was found in the quest line given by Miyani.
In this quest, you visited the quaggan, hylek and largos who all had some information regarding the karka. The hylek had you make some kind of mixture from alchemical ingredients in the area which I assume was then developed into the solvent used in phase 2 of the event.