Can this be made without a microwave? Would the chocolate need to be tempered?

You can easily do it in a double boiler or a hacked double boiler (with a bowl atop a pot of boiling water)!

I don't see why you wouldn't be able to make it on the stove. I would leave some chocolate on the side, put the rest in the pot with the coconut oil until its almost melted all the way, and then add the chocolate you set aside. Stir until the added chocolate is combined.