The last option is probably one of the most realistic. Sean Payton has already said multiple times that the quarterback he envisions being the leader of the team next year is already in the quarterback room meaning either Jameis Winston or Taysom Hill.
If Winston ends up leaving, then that statement only leaves Taysom Hill. Hill did have the opportunity to replace Drew Brees last season for four games when Brees was on the injured reserve list with broken ribs and a collapsed lung.
He went 3-1 in his starts for the Saints, and he threw for 928 yards and four touchdowns over the course of this season. Hill has the potential to be a stopgap quarterback, but I do not think that Hill is the long-term type despite his massive contract.
The New Orleans Saints are going to have to figure out an answer to the scenario that Jameis Winston leaves. If in fact, he does, then one of these four options is cheap, talented, and could help lead this team to another playoff birth.