· Are there universal characteristics of belief systems that are common across people and time?

Answer 1

The oldest identified belief system is Shamanism which appears all across the planet and even survives today. You can see evidence of it in rock art thousands of years older than civilisation.
Monotheism has nothing identifiable in common with shamanism, thus there is little if anything that is universal.
The closest you can get probably begins and ends with "I think therefore I am."

Answer 2

(1) Trinity in structure

All religious or secular systems of belief, even political systems, have a three-part structure. The reason for this is that each human being is physical, psychological and spiritual in nature. So any collective system of philosophy or laws defining or regulating human behavior and relations in society also reflects three levels, from "individual/physical" to "collective/global" or "spiritual/divine" and the intermediary level joining the two (secular systems may call this connection the collective conscience or love of humanity and brotherly love, while Christians may recognize this as the love of Christ rejoining God and humanity by sacrifice and redemption). In the Christian Holy Trinity, Christ is the level of the law joining God's divine kingdom with the Holy Spirit of humanity or the healing spirit of the church or people. In Buddhism, the three refuges are the Buddha, Dharma, and Sangha, where Buddha represents perfect Wisdom or knowledge of God's truth and creation, Dharma are the laws or teachings which Christians call the Word of God fulfilled in Christ, and Sangha is the peaceful community or order, or the equivalent of the people or church joined together in the Holy Spirit of communion. In Constitutional government, the Judiciary acts as God in making judgments, the Legislative acts as the body of laws or conscience of the nation, and the Executive carries out the laws physically. So even secular systems reflect the trinity of human nature, where the human conscience is the psychological level influenced by both spiritual and physical factors in life. (In psychology, the superego, ego and id are the three factors driving human behavior.)

(2) Theme of salvation by Messiah
Different mythologies and religions prophesy the coming of a future Messiah who will save humanity. The Jewish and Christian prophesies are written in the Bible, and Christians and Messianic Jews recognize Jesus as the fulfillment. The Muslims believe in a final Iman, and the Buddhists believe in the coming and return of a Maitreya Buddha, that can be interpreted or associated with the spirit of truth, Jesus and the Holy Spirit in the final days, bringing enlightenment and salvation.

(3) The Golden Rule of reciprocity.
Natural law on doing unto others.

http://www.teachingvalues.com/goldenrule...
http://www.worldreligionday.org/golden_r...
http://www.religioustolerance.org/recipr...

The reason this is common to all religions is that it reflects a "natural law" that is even found in secular government.
That there should be equality among all people in order for there to be justice and peace, as needed for both political and spiritual freedom.

Answer 3

I would say eating, love issues, living "indoors"