I think that's too small.
With 5 pounds of meat, I would shape the meat into a large loaf and put it in my roasting pan that I use for smaller turkeys (~15 lbs or less). If you have one of those removable rack things, you can cover the rack in foil and then it is easy to lift the meatloaf out and slide it off onto a platter.
Alternatively, you could make smaller ones, seasoning them all differently.