QI have 2 copies of this follower on my field. If I choose option 1 when resolving the automatic ability of one copy, can I choose option 1 when resolving the automatic ability of the other copy in the same turn?

AYes, you can. The "choose one that you haven't chosen this turn" restriction only applies to that individual copy.

QWhat counts toward "the number of times your leader has lost defense this turn"?

AAny time your leader takes damage, is given -X defense, or has its defense changed to a lower value counts. For example, paying the cost of Zealot of Lust's activated ability.

QIf I can't select an enemy follower on the field, can I still choose option 1 to have nothing happen?

ANo. If you can't select an enemy follower, you would be required to choose option 2 or 3.