Neither use as an implementation language nor syntactic similarities make one language a dialect of another. Consider that Java is commonly implemented in C++, and its syntax was designed to be easy to learn for C++ users. Yet nobody calls it a dialect of C++, not even when squinting really hard.

Erlang's computation model is functional, like Lisp, unlike Prolog.

Correct, although I would assert Prolog shares many concepts with Lisp.

It does. In Prolog, data is code is data as well.