Machines for the sole purpose of hosting our genes and ensuring their survival. That's one common way of looking at it.
Yes that's pretty much it. Humans are an assembly of natural materials shaped by a genetic code acting upon the surrounding environment.
When you then try to apply a concept such as 'free will' upon such a concoction what are you really asking? Whether the interactions between grown neurons through this process can react to an environment independently from themselves? Such a notion is clearly illogical and provides no insight into anything.