While answering questions is certainly something we support, you could have left of the 'seems' and 'maybe' simply by checking WoWhead and viewing the proc mechanics for each weapon. Doing your research is something we require around these parts.
I'm not 100% certain with the staff but vishanka does not have a ICD if I remember correctly. Or at least it is very short because I see it procc quite often on single or multi target with my hunter alt. Together with the gcd and reset auto shot timer you'd invoke by swapping each time I believe it will not be worth it.
The staff may have an internal CD but the time between proccs is not too long either and I don't think you can unequip kiril one the procc went off because it should fade.
Weapon swapping in general has probably been no benefit to any class since blizzard introduced the gcd after swapping weapons.