You raise some interesting points here that I definitely intend to ponder.
Dietrich Bonhoeffer is, in my mind at least, one of the modern giants of theological thought. I have long considered him a martyr, but his death was not actually for the the Faith. However, he was clearly prepared to die for the faith, but the Nazis executed him (there was no record of the trial) for other reasons. The Catholic Church (and I believe the Lutheran and Anglican Churches) have always listed Saint John as a martyr even though he didn’t die a martyr’s death, he was placed in boiling oil and emerged unscathed when he should have died and was fully prepared to die.
On most Western calendars the festival of St. John is titled “St. John, Apostle and Evangelist”. The same title is used for St. Matthew. Luke and Mark are titled as simply “Evangelist”; the other (non Gospel-writing) Apostles such as James and Bartholomew are titled as “Apostle”.
All except St. John the Apostle and Evangelist are celebrated with red vestments, John the “martyr in will but not in deed” is celebrated with white.
Now you’re cooking!