Weapon Animations

Hello! I'd like to ask a question that might be simple for people experienced with animating.
I want to make some animations for my top-down 3D action/stealth game. The idle, running etc. animations are simple enough to make in Blender. But when it comes to animating my character with weapons I'm completely out of the loop.

Do I animate the character in Blender with the weapon already "attached" to it? Or should I animate swings with the character empty-handed and attach the weapon in Unity?

I want to make a few "classes" of animations, like swords, handguns and rifles, since having different animations for every single weapon would be insane in my case.

Thanks for replying and pardon my cluelessness.