Possibility to retrieve BIP39 mnemonic (24 words English dict) from BIP39 (hex) seed?
This is not possible.
The seed words are converted to the hex seed through a process involving a one way hashing operation - it is not possible to go the other way.
That said, as long as your hex seed is the tree root, keeping that safely would allow you to access all your coins, although it would make importing it into a wallet somewhat difficult.