West was due to headline the festival in July but drew criticism over past antisemitic comments.
Craig Lewis-Williams needs specialist care for the rest of his life following the November 2021 attack.
Orla Wates, reportedly killed in a road accident, is remembered by her mother as "beautiful, independent and very funny".
Detectives determined there was "insufficient evidence" to bring criminal charges against the unnamed man.
Metropolitan Police detectives are appealing for information as part of a murder investigation.