There will be serpentman weapons for certain as you can see their exceptional recipes on blacksmith thralls. I cannot comment if there will be armors as well since my armorer did not have those recipes. There is also obsidian as a resource for new weapons and armors.
As for building materials, I am guessing no. If anything we need a T4 set of building materials given the change to raiding.
apparently you can find serpentman weapons, and obsidian weapons and tools in Admin Panel in testlive.
And plus you will be able to get receipt of obsidian weapons and tools in volcano dungeon.
I don’t think they will release t4 building. But I wonder if they have plan for another style of t2/t3 building for jungle/swamp version that’s what I am saying.
In the swamp / jungle biome (swungle as they called it xD) we will have the ability to build tree houses. Which sure means they will add some pieces to that. At least thats what I expect