As to Judas, no. I do not see him as a believer at anytime. I think he was always there for the very reason that finally pushed him into selling our Lord for money. It was always in his heart.
Yes, Judas hung himself on guilt and condemnation but he also cast out devils and still followed Jesus even after Jesus said whoever eats my flesh, drinks my blood will have eternal life, Jesus' thousands of followers left Him after He said that but Judas stayed, and when the disciples asked who would betray Jesus, none of the disciples knew that it would be him.
Judas was a treasurer, not a zealot and even after Judas betrayed Jesus, right after the kiss, Jesus called Judas "friend".
I think pointing out sins in other people and being obsessed with sin can cause you to hang yourself (not literally) on guilt and condemnation and the prophecy needed to be fulfilled in Zechariah 11. Did Judas commit the unpardonable sin?
John 13:29, Since Judas had charge of the money, some thought Jesus was telling him to buy what was needed for the festival, or to give something to the poor.
Judas didn't want the money from the Pharisees in exchange for Jesus' death, he wanted the Pharisees to sit down with Jesus and work things out because he figured if they got to know Jesus like he did, well. He didn't know they would hate and reject Jesus. So, why did Judas want the money? Being a treasurer, he had a mentality about money and what to do with it.
John 12:4-5, But one of his disciples, Judas Iscariot, who was later to betray him, objected, “Why wasn’t this perfume sold and the money given to the poor? It was worth a year’s wages.
Mary's perfume was worth a lot of money and it was poured on Jesus' feet. Judas saw this as a big waste of money.
John 13:30, As soon as Judas had taken the bread, he went out. And it was night.
A spiritual description of what Judas walked out of, he walked out on the light of the world.