Can't speak for the other classes, but Mage pets get innate dual wield starting at level 44 (
https://wiki.project1999.com/Magicia...by_type_of_Pet), and I suspect this is true for Necros also.
As for pet weapons, I like to use the stun whips from South Karana gnolls, but really I tend to just throw any random (but cool looking) weapon I find onto my pet. The proc won't make a difference in a raid setting, but I like having my per look unique when it stands next to several carbon copies.