Aliens
The alien people are just that, people, same as us.
They are as alive and physical and mortal as we are.
Most other races of people in this part of the Universe are much longer and further advanced and evolved than we humans on Earth are yet.
They also know their neighbors and help each other, so they have some benefits of shared knowledge, experience and technology between them.
They live longer lives of higher quality, and humans will too.
They are also advanced spiritually - imagine our little psychic abilities evolved another million years and see what we can do.
All races of people believe in the one God because God himself teaches at each world of intelligent life.
Angels
The Angels are just as real, but they are not people like us.
They are ageless, immortal beings created to serve as emissaries of God to each and every one of his children.
All Angels work directly for God.
All races of people in all the Universes, known and unknown, are God's children.
God
Think naturally and spiritually about these things, not religiously, because it is a very sad thing when, as people realize how silly religion is, they throw God away with it.
Religion always changes, but God is always the same and is bigger and more wondrous than any mortal ever imagined.
