The addition of a large predator to this already unconventional environment was, from Melanie’s perspective as a teenager, something she did not choose and could not meaningfully refuse. She was fourteen when the photographs were taken. The decision to bring Neil into the home had been made by the adults. The conditions under which she appears in the photographs were the conditions of the household she lived in.
What she thought about the arrangement — what she said to her mother, what she said to her stepfather, what she said to no one — is not recoverable from the available public record. She has not, in the accounts that are publicly accessible, given extended interviews specifically about her experience of the domestic lion period as distinct from the Roar production. What is documented is what happened to her during the production itself, which was considerably more severe than anything that happened during the domestic period.
The attack that Griffith sustained during the Roar production was serious. A lioness attacked her face. The wound required approximately fifty sutures, and the physicians treating her initially feared she might lose vision in one eye. She did not, and the injury healed, but the fact of the attack — and the fact that the attack is visible in the finished film, because the production continued even when cast members were being injured — reflects something about the environment in which she had been placed.
She left the production at one point and was replaced by a performer named Patsy Nedd before eventually returning to reshoot her scenes. The Wikipedia account of the film notes that Marshall’s treatment of Griffith — specifically an incident in which her safeword was ignored — was cited by John Marshall as connected to the divorce between Marshall and Hedren in 1982.