Any tag can be added to the definition of a thing by hitting the blue "Tags" button in the upper right of the editor. The text before "." is the Tag Group, and the text after "." is the Tag ID, when adding a tag through this button, the "." is not included in either. Alternately, in the central column, if you scroll down to the section for "Display Information", you will see a line for "Available When Equipped?". Checking the box there will automatically apply the tag I mentioned.
Adding a variable amount to initiative, the simplest way to handle that would be to use the #situational macro, targetting the Initiative pick on the hero. Like so:
Code:
#situational[hero.child[Initiative],"Add 1d10 to roll",field[thingname].text]
There are more complex ways to let the user enter a specific number which they rolled, but I'd say keep it simple for a start.
For pre-setting the target of the Bane power when you build a pre-built weapon, copy and take a look at the weapon "Seaspike" from the "Ruins of Azlant" AP. In the set of buttons in the upper right, there is one for Gizmo, open that, then a form will pop up with a button for "Bootstraps", and in the list of bootstraps you should see the bane power. It has a field set where it is bootstrapped here, to make it Bane vs. aberrations.
You can't manipulate the values with scripts currently, as I said. That will need to wait for the update.