Can FileVault protected data be accessed if the hard drive has been NON securely wiped?
The information is there in a cryptographically erased format until you over write the data with a new file or re-encrypt the space with a new key. In some narrow way, the data is there, but no one can reconstitute it. 

Specifically, each individual block on the storage was uniquely encrypted so you would need mathematically impossible amounts of processing to crack each block and then start the normal data recovery process.

The moment the large cryptographic key that was derived from your pass phrase was erased, you lost all practical and most impractical methods to recover any data from the still encrypted storage.