For all regular languages L, by the Myhill-Nerode classes, all state-minimal DFAs for L are isomorphic. On the other hand, "a regular language may have many non-isomorphic state-minimal nfas". What about Unambiguous Finite Automata? Every DFA is also a UFA, so every regular language has at least one UFA. The natural numbers are well-ordered, so in turn every regular language has at least one state-minimal UFA.
Is there a regular language whose state-minimal Unambiguous Finite Automata are not all isomorphic to each other?