Firstly, And ifif I by Beelzebub cast out devils, is rhetorical. They accused Jesus of calling other forces into play rather than God - not having any belief in who Jesus really was. In other words, it's like saying, 'he who lives by the sword, will die by the sword'. Matt 26:52 By what you trust in, that will be your standard. (Just as he rebuked the Jews, saying, the devil was their father, they will be held to account under the law if they live by self, evil and lies instead of honouring God John 8:44)
Jesus came to deal with sin and death - he cannot do that under authority of Satan - hence the 'kingdom divided' spiel in v25, he does it under God's authority. Satan will never forgive anyone - if they appeal to him as a judge, they are dead already!
Apostles judging the twelve tribes of Israel and the saints will judge the world are the same thing in that they will be under Christ as chief judge - this authority given him by the Father.
Jesus is the only way to salvation, but first, each must be brought to account of their total failure at 'being good' - then, through the repentant heart that God provides, they may finally accept Jesus' sacrifice to cover their sins too. Judging is under the law of life and grace, OR the old law of sin and death.
If If one does not recognise God's authority in Jesus (as the Pharisees did not), they reject God and are left with the hard result of sin - death! If one refuses grace, through Jesus' sacrifice, the law still stands and eternal death awaits.