The barebones minimum requirement?
I guess it is to be invited.
John 6:44 "No one can come to Me unless the Father who sent Me draws him, and I will raise him up at the last day. "
But I don't think the Father draws them in a barebones minimum way.
Matthew 4:17 "From that time on Jesus began to preach, “Repent, for the kingdom of heaven is near.”
So repentance follows the call and is an essential part of the process. Otherwise, Jesus would have been preaching, "Relax, I've got this covered" instead of "Repent". I don't think we even know how to repent without Christ. Forgiveness is forgiveness for what we have done and do. Repentance is on ongoing change of direction, an orientation towards Christ, a course correction guided by God. The more a life is lived in repentance and obedience, the less forgiveness is required day by day, and the more that life is transformed and changes.
Repentance without Christ would be like trying to navigate with a compass that always pointed towards yourself instead of True North. Christ without repentance would be like having a compass that worked and not using it.
The sacrifice and resurrection and forgiveness of Christ make all of this possible. It's an invitation and an undeserved honor. We need to respond as such. I don't think that's something that is done in a bareboned minimum way.
Matthew 22:10-14
10 So the servants went out into the streets and gathered everyone they could find, both evil and good, and the wedding hall was filled with guests.
11 But when the king came in to see the guests, he spotted a man who was not dressed in wedding clothes.
12‘Friend,’ he asked, ‘how did you get in here without wedding clothes?’ But the man was speechless.
13 Then the king told the servants, ‘Tie him hand and foot and throw him outside into the outer darkness, where there will be weeping and gnashing of teeth.’
14 For many are called, but few are chosen.”