there was several chiefs in the age of judges
Yes, during the centuries of the Judges and Kings. During Second Temple times there were Jews and non-Jews in Israel (Judea).
There is no one theme to the stories. Two recurring themes are Israel's unfaithfulness and God's faithfulness. In the book of Judges there are several recurring themes in the stories regarding the nation of Israel eg backsliding, oppression, repentance, deliverance
Deborah (Judges ch.4).see also:more about the Judgesmore about the Israelite prophets
Eli and Samuel were the last two judges of Israel before the era of the monarchy began.
During the time of Samson, Israel was ruled by a series of judges rather than a king, as the Israelites had not yet established a monarchy. Samson himself was one of these judges, serving as a leader and deliverer for Israel. The period of the judges occurred before the establishment of the Israelite monarchy, which began with Saul. Thus, there was no king ruling over Israel when Samson's story took place.
The seven-fold cycle of Israel consisted of Israel serving GOD, falling into sin and idolatry; being enslaved, crying out to GOD for help. A judge was raised up and Israel was delivered; cycle repeated.
No. During the times of the judges there were many cycles of backsliding, oppression, repentance and deliverance. God repeatedly raised up judges each time Israel began to take on the idolatrous practices of the people they failed to drive out of Canaan. Israel became oppressed by these Gentile nations when they repented and cried out to God, God delivered them through judges (military leaders) who over threw the oppressors.
Not all the Judges were men because one was Deborah.
The judges were sent, by God, to deliver Israel from their oppressors. The book of Judges is a repeating cycle of Israel turning away from God, then God allowing other nations to oppress Israel, then the people crying out to God for help, and God sending a judge to deliver them.
The prophet Samuel served as a bridge between the Judges and the Kings of Israel. He anointed both Saul and David as the first two kings of Israel, transitioning the nation from a period of judges to a monarchy.
According to the Bible, the first named Moabite who goes into Israel is Ruth. However, it is highly unlikely that she was the first Moabite to enter Israel as the Moabites and Israelites had economic and political relations during the period of the Judges as well.