Yes, you can remove the product with hyaluronidase. You may require a couple treatments, so ensure you allow enough time for this before the fat transfer.
All the Best.
Personally, and each surgeon is different, I like to see the complete defect before fat grafting. It makes sense to me to then fill the area once the material has dissolved are resorbs. However, layering may not be a bad idea either if the change is gradual.