I'm not Mark, but I'd like to jump in and answer a couple questions from my own theology. I hope Mark gets back on in the morning and corrects me where necessary
. I have great respect for Mark and his school.
Moses comparable to Jesus: if you look at the simple definition of the word "messiah" as a "deliverer, " then yes Moses certainly was one. So were Joseph, Samson and Saul, just to name a few that come to mind. They all saved the Jews from something/someone. Jesus alone was God incarnate, and saved humankind from something no man ever good, their own sins. That is essentially the crux of the matter of Christianity as a faith vs. a theory: if you believe Jesus is who he said he is, then it means everything. If you don't believe Jesus was who he said he was, then it means nothing. If not the son of God, then He's historically insignificant.
Holy Spirit doesn't get much airtime in the Bible: To answer your question at face value, the Holy Spirit doesn't get much airtime because the Holy Spirit was introduced as such by Christ, and the Bible ends shortly after Christ's death.
However, the "Spirit of God" is described many times throughout the Old Testament. Whether that's the same as the "Holy Spirit" described in the New Testament is a matter of individual trinitarian theology, and there are many opinions in that topic.
On the matter of the Trinity--the "Three in One"--some people focus more on the three and some on the one. My personal opinion is that the Trinity describes 3 manifestations of 1 diety, and God gets the same airtime no matter which manifestation is displayed. The New Testament describes the Holy Spirit as both the "Spirit of God" and the "Spirit of Christ"; Christ called it "My Spirit" and also said "I and the Father are One." My theology says they are fully the same, and therefore saying the Spirit gets less exposure is like saying my left hand has fewer friends than my right because fewer people shake it. It's irrelevant. Like I said though, there are many different opinions on the Trinity and I look forward to hearing Mark's.
Answers in the Bible about mysteries/ extraterrestrials?
The Bible is not intended to answer every question. It's meant to answer the important questions, those of faith, God and morality. There are many, many things simply not addressed in the Bible. Like microbes, viruses, DNA, metallurgy, petroleum, computers, wireless technology, astronomy, modern medicine, machinery, etc. There are simply a lot of things that the Bible is not intended to address, and we humans get the joy of unraveling the mysteries over the millennia. There are fascinating mysteries in the history of the world like you described, and just because the Bible doesn't answer them doesn't mean they're in conflict. Why would they be? And I don't know if Mark's school teaches anything about UFOs, but I wouldn't expect them to any more than a medical school. Why would they?