We prove that the Drinfeld center of a fusion 2-category is invariant under Morita equivalence and under taking the 2-Deligne tensor product with an invertible fusion 2-category. We go on to show that the concept of Morita equivalence between connected fusion 2-categories recovers exactly the notion of Witt equivalence between braided fusion 1-categories. Then, we introduce the notion of separable fusion 2-category. Conjecturally, separability ensures that a fusion 2-category is 4-dualizable. We define the dimension of a fusion 2-category, which is a scalar whose non-vanishing is equivalent to separability. In addition, we prove that a fusion 2-category is separable if and only if its Drinfeld center is finite semisimple. We then establish the separability of every strongly fusion 2-category, that is fusion 2-category whose braided fusion 1-category of endomorphisms of the monoidal unit is Vect or SVect. We proceed to show that every fusion 2-category is Morita equivalent to the 2-Deligne tensor product of a strongly fusion 2-category and an invertible fusion 2-category. Finally, we prove that every fusion 2-category is separable.