How do you do *that*? Presumably the defense agreed to these jurors.Ineffective legal counsel might be a more effective avenue of appeal.As might the empaneling of a six member jury instead of twelve.
I do not know, most appeals are on technicalities anyway.
In jury selection either party can challenge a particular juror for cause, i.e. that because of something specific to that juror, the juror is not impartial. Much of the selection process is taken up with this. That is the reason for all the questioning. The judge may or may not agree that a challenged juror is biased and can deny a challenge. Each side then has peremptory challenges which they can use to strke a juror for any reason they want and they do not have to explain. Usually each side has 3 challenges.
So it could happen that a juror that was challenged for cause ends up on the jury anyway because the court disagreed and the defense used up its peremptory challenges on 3 worse jurors. This could give a basis for appeal. Tough argument however.