Re: Is a license needed for VASA? Is a license needed for each copy? Is VSI needed to have VASA? Are they mutually exclusive? Is VSI needed to have VAAI?

Assuming you are referring to EMC arrays.

License for VASA:  No.

VSI required for VASA:  No.  They work fine together, but neither requires the other.

VSI needed for VAAI:  No.  VAAI is active with or without VSI.