It might be easier to understand what was going on in the Jewish community in the first centuries B.C.E. and C.E. is we use the analogy of Christianity in the 19th and 20th centuries.
While Christianity has always had schisms and heresies, they tended to be large movements that shifted whole populations to one belief or another. Then, in the 19th century, several different ideas were either invented or took on new life that did not lead to schisms so much as a growing plurality of belief within Christianity.
John Darby invented a new way to look at the book of Revelation, (dragging Daniel and Ezekiel and odd passages from Paul and Luke into the mix), to create the series of beliefs that we see displayed in stuff like the Left Behind fiction. (And even the people who believe the End Times are upon us have split into three separate groups, divided by what order they believe the Rapture and the Tribulation will occur.) Soon after Darby, discovery of ancient texts of the Gospels gave impetus to a long-simmering approach to evaluate Scriptureon the basis of literary analysis. This led to an effort to discover the “historical” Jesus which, in turn, led to questions about how accurate the Gospels were regarding miracles and led Bultmann to put forth the idea that even central mysteries of Christianity, such as the Resurrection, may have been expressions of faith and not depictions of real events. Faced with these sorts of challenges, a number of Christians chose to interpret Scripture even more literally than it had traditionally been seen. The increasing secularization of governments with the attendant greater religious tolerance led (slowly) to lower barriers between Christian religious groups, giving rise to the Ecumenical movement with many groups being more willing to share (and borrow) concepts from “competing” groups. Developments in science further challenged the literal accuracy of some biblical passages and new sciences such as psychology challenged the ways that some churches viewed marriage, homosexuality, and other beliefs that were wholly embedded in Christianity, but not central to its beliefs.
As a result, we can survey “Christianity” today and find people who hold beliefs ranging from an absolute position of biblical literalness to people who hold that the bible is a loose collection of nice sayings (with some frightening claims). We can find “Christians” who belive everything from the idea that God ordained that no one could have sex until marriage and that marriage must be a heterosexual union indissoluble before death to people who reject some or all of those assertions. We can find Christians who believe that Hell is a physical place below the surface of the Earth (with arguments whether people awaiting the Final Judgment are aware or not or even temporarily non-existent) and Christians who believe that Hell is living in the spiritual presence of God and realizing how badly they have sinned.
So if you were to say “What did Christians believe in the 20th century?” the answer would have to be “It depends.”
In the last 200 years before the destruction of the Temple in 70, Judaism had an analogous situation. (Don’t try to line up too many of the differences too tightly; this is just an analogy.)
The major centers of Jewish scholarship were located in Babylon and Alexandria, not Jerusalem, although there was a movement under way to “bring it home.” Meanwhile, the area around Jerusalem underwent several physical and psychological wars for the hearts of the people. When the Macedonian/Greek/Syrian Antiochus Epiphanes attempted to destroy Judaism as a religion, it led to the Maccabean revolt. However, since it was a war waged as a civil revolt, it led to calls for support from outside forces. Over the next hundred years or so, different religious and civil factions attempted to maintain power in Judaea while either relying on or opposing the interference of the outside Greek and then Roman powers. This led to internal religious politics getting entangled with the civil politics, leading to a number of different sects. (The Essenes, for example, were not simply some group of people with a mystical view of life; they were a group who believed that the Jewish priesthood had been corrupted in the internal strife and they were looking for the day when a leader/savior/reformer would come forward to wrest the control of the priesthood from the Hasmoneans and “restore” it to its legitimate state.) Meanwhile, the Jews of the Diaspora, mostly uninvolved with the revolts and politics in Judaea, were continuing to follow their own theological paths. To a certain extent, they did not even get heavily involved in the Judaean revolt that led to the destruction of the Temple in 70. (This separation came to a screeching halt in the revolt of 132 when the Roman emperor decided to assess a tax on the Jews of the diaspora to finance his suppression of that second revolt.)
So when we look at the Jews among whom Jesus lived, we have to consider that they might have been Sadducees (the ultra conservative wing in power that did not believe in the new-fangled ideas about a resurrection) or Pharisees, the liberals who did believe in a resurrection, but wanted to ensure that everyone practiced the faith correctly and so, when they were briefly in power, set up schools throughout Judaea to educate even the poorest boys. They might have been among the people who were chafing under Roman rule, writing apocalyptic tales of the defeat of the enemies of the Jews (in the tradition of Daniel and the Christian book of Revelation). They might have been people who shared some of the ideas held by the Essenes that the current priestly leadership was corrupt.
However, trying to figure out what “they” believed is more problematic.
After 70, and particularly after 132, it became a lot easier, of course. Much of the extraneous theological speculation that had developed when Judaism was free to express itself and explore different concepts was cast off when they entire people came under attack. This is a pretty human situation. The Catholic Church in Poland is one of the most conservative groups in the church, having suffered over 50 years of direct suppression.
It is possible that we can identify some of the answers to your questions, but it is also possible that we will get it wrong. Judaism after 132 is quite different in its explorations (not in its essentials) than Judaism in 67, and most of your questions have to do with theological explorations, not core belief.
I will say that the ideas regarding who gets “saved” and so forth have a decidedly Christian feel to them. It is possible that these questions were discussed in first century Judaism, (and their appearance in the Gospels indicates that some such belief was prevalent among some people, otherwise the words of Jesus would have sounded like gibberish to his audience), but how firmly rooted they were among the people or the scholars it is difficult to tell.
