While I can't speak much to the content of your answer and its correctness (thought it does seem to provide a good reason why Aeneas and his guys didn't settle on Sicily), I think I can help out a little bit with the grammar.
In somno Aeneae Di Penates ad stare ei visi sunt et monuerunt ut eum et socii sui e Creta egrederentur.
Since the subject of the main clause is di penates
, anything that is reflexive would properly be referring back to them. So, in the ut
-clause you have eum et socii sui
in an attempt to refer to "Aeneas and his buddies." I think eum et socii eius
is what you are looking for.
I know that there are some reasons why a reflexive can be used to refer to the subject of a subordinate clause, but I don't have time to look up a reference at this moment. In any case, di penates
are still the subject of your ut
Also, it looks like you might have a bit of a typo: I think for ad stare
you meant adstare