I doubt the Disciples had inside information about the San Hedrin Council. I believe Judas believed Yeshua was supposed to kill the Romans and instead He preached to forgive them. Judas probably had his own endeavors and Yeshua wasn't moving in the right direction.Judas' damnable sin was that he didn't believe in Christ. He was a follower of Christ for 3 years, so he was a Christian in that sense, and he apparently believed Jesus was Israel's messiah, but he believed that Jesus had come to save the nation of Israel from the Romans, rather than to save the people of Israel from their sins.
IMO the rulers convinced Judas that if Jesus wasn't stopped, the Romans would take away their land and nation. The nation was obviously more important to them than was the truth.
Then gathered the chief priests and the Pharisees a council, and said, What do we? for this man doeth many miracles. If we let him thus alone, all men will believe on him: and the Romans shall come and take away both our place and nation. And one of them, named Caiaphas, being the high priest that same year, said unto them, Ye know nothing at all, Nor consider that it is expedient for us, that one man should die for the people, and that the whole nation perish not. John 11:47-50
This fear may have motivated Judas to betray Jesus to the rulers thinking that the rulers would have a talk with Jesus to explain this to him. Which would explain his remorse when he realized they meant to kill him instead.
If all of this is true, then Judas wasn't a true Christian, but he was a Christian zionist who saw Israel's promised redemption as being deliverance from Rome rather than as being deliverance from sin. So Judas appears to be the forerunner of Christian zionism, and those who follow that doctrine can be considered to be following in Judas' footsteps.
But to kill yourself after Yeshuas capture and death probably means he felt extremely guilty for his actions and instead of going back for forgiveness just jumped onto a short rope.