The likeness clause in the LFL contracts with actors is iron-clad.
They can produce figures of ANY of the characters from the existing films in the actors' likenesses in perpetuity.
If they never make another Leia product that looks like Carrie Fisher, it would be by choice.
But surely her death changes things? Even if the contract gives LFL rights in perpetuity if her heirs challenged it then Disney would be doing something potentially at odds with public opinion if they ignored the wishes of her heirs.