Do secondary weapons' bonus apply?

if you're always shapeshifted, you're necessarily never using the weapon set with that staff equipped. it doesn't matter what you equip on this weapon set because it will never apply, whether it be a staff or shield or anything else.

You bind skills to weapons. While the skill is being used, the weapon and its stats are active. Otherwise, it is disabled and does nothing.

No but you can get the passive to equip a scepter + talisman if you want

Nope but you can lock your weapon to both weapon swaps, set up slightly different talent trees for each weapon swap, assign abilities to only one weapon set and the game will automatically and seamlessly swap between those talents as you use your abilities.

For example, you could add extra freeze buildup nodes to Lunar Assault (or whatever that ice swipe freeze ability is) and only run it on weapon set two so that you freeze stuff faster and then run crit nodes or attack speed or whatever with all your other abilities.

Dunno if the way I’m explaining it makes sense :D