Legendary Weapons in HoT
The weapon models will likely be data mined before release, but they probably won’t tell us anything about them until right before or even not at all.
You will be able to craft one copy of each Precursor.
As for reveals, I believe I remember they said more info on that would be forthcoming. We can pretty certain recipes or mats will prob not being further elaborated on so a not to unbalance the market on mats.
One other point, in the Precursor Mastery lines, the new ones are the final set you unlock. ie, you have to train the other lines in the Precursor Mastery first, then the HoT Precursor one before you can craft a HoT Legendary.