Using the wood from grape vines is perfectly fine to use, as are the leaves. However, I would steam or boil any leaves first as this process removes the fuzz on the leaves that can make the leaves slightly bitter.
Here's the biggie though...if the vines and leaves have been treated at all with any kind of pesticide, baking and freezing will get rid of insects...but not the poison. If they've been treated, I wouldn't use it at all.