So, I am going to borrow some stuff from
@Alicia and two members of the TPS Discord: Wallin Ballin & Fangzthewolf.
If this deal allows Embracer to be the sole group for theme park licensing, that then cuts out the Estate from being involved. Hypotehtically speaking, all they'd need to do is to make a deal with Embracer, and then the filmmakers involved (that being Peter Jackson included) for this.
Granted, as we don't know what Embracer would want, but as I've come to understand it, Embracer's more on the terms of hands-off. Meaning this could be a matter of specifically Middle Earth Enterprises, Universal, and the creative parties involved on the particular stories?