Dreamteam67: Maybe, but I don't think familiars had inventory slots even in vanilla. Once the familiar is out of your pack, they work more like a summons or a charmed monster, tagging along with the party but you don't have much direct control.
Hickory: Yes you do. You have complete control, at least with the Co8 mod you do. There are certain actions that are invalid, sure, but you do have control of it, and it has an inventory.
How? All I can do with the familiar is move it around, and only when we are not in combat. As soon as combat starts, the AI takes control and it basically attacks the nearest enemy and there is nothing you can do. It doesn't even have its own sight range, so it is useless as a scout. It doesn't have a radial menu, it doesn't pick anything up, the "I" hotkey doesn't work, there is no inventory screen that I can find. As far as I can tell, it functions exactly like any other summoned creature, except that when it dies your Character loses exp.
How does that constitute complete control? I am using the Co8 mod 8.01NC. Are there more modules to activate?
But honestly, unless the familiar can auto-loot a corpse, it isn't going to save any time, because you would have to load each piece of equipment into its inventory individually. SO you might as well just do that directly in the store.