Im not sure but it feels like static shot goes after castspeed anyone know for sure?
Attack speed increases the speed of autoattacks and also increases damage of abilities (Not sure what the dmg increase is, its rather odd that attack speed affects the dmg of abilities)
Cast speed increases the speed of abilities, cast animations plays out faster and you also launch projectiles faster.
Not sure if Cast speed also increases the dmg of abilities, didnt really test that yet.
Unless Salan put unique modifiers to an ability, it should only get increased cast speed from cast speed and not attack speed.