Terminology about computation and Finite algebra
Such algebras are called functionally complete. Also, what you call terms are actually called polynomials. In standard terminology, term operations have a more restricted definition that allows variables and the basic operations $f_i$, but not constants from $E$. Algebras that satisfy the stronger condition that every operation is represented by this kind of a term are called primal. See e.g. Burris&amp;Sankappanavar, A Course in Universal Algebra.