Yes, you can cannon skeletal wyverns. However, depending on what you are going to do there, it might not be very effective. If you are going to try and safespot them, it is not going to be very fun to reload your cannon and it can be a very effective strategy to kill them. If you choose to use mage, you are not going to need a cannon too. Your attack bonus is not going to be high enough to hit them often and accurately for a lot of damage.  If you are meleeing the skeletal wyverns, I think using a cannon is going to be a very good idea. You are going to hit them high and attract them towards you while fighting them, so you can do it pretty AFK. I would recommend you cannon them when you are on a slayer task. Then you can go to the higher level, where almost nobody is killing them.