Complexity of CFG grammar for a regular language
A regular grammar is context-free. So regular languages are
context-free.

Every regular language has a right regular grammar, which is simply derived from a finaite state automaton for that language.

Every regular language can be recognized by a deterministic finite state au tomaton. From that deterministic FSA you can construct a right regular grammar
which is LL(1) since you can decide what to do for
parsing by simply looking at the terminal on the rules applicable at any time. There always is only one such rule. Actually you do
not even need the pushdown, and use the non-terminal for the states.
(this is a bit informal, but it is so simple being formal seems
silly).

The key part is producing the deterministic FSA.

So, yes, every regular language can be generated by a LL(1) grammar.

A LL(1) grammar is always unambiguous, as it allows constructing a
deterministic push-down automaton. So it is unnecessary to specify
that it is unambiguous.

As for your language, it seems strangely defined, and I wonder whether
you copied that correctly. What is the "$+$" supposed to mean ?