The loa are spirits of voodoo but also pertain to more than just voodoo. Just because it's a practice that involves a popper does not mean it's not voodoo. There's a good reason why these poppets are called voodoo dolls.
Now as for making a doll. You can make a doll out of clay. Just get some model gray clay and shape it to a human figure. If you are really tallented with cutting and sewing, you could shape and cut out from close a basic figure of a person, sew a couple of these together, and stuff it with cotton. Of course I'm sure that would be harder than it sounds. I have also seen plenty dolls made by the person tying a Buchanan of small sticks and twigs together shaping them as the human body. And of course you could try to find a store that sells poppets and buy some.