Q: For the new bonus when confirming, does the second card I confirm have to come from my hand? 

A: Yes. If you are confirming a clue card from your hand, if you have a second card of the same name in your hand, you may confirm that card without using an additional action or spending additional ideas.

Question regarding card 66B
Q: Does this mean we must try to solve the Suspect again for my master case?

A: Yes. You will need to solve the Suspect again, as well as the last new aspect. You will score points accordingly (see card 76A)

Card 39A has a lock. How do I unlock card 39B?
This information is on a need-to-know basis. If you have not been told to flip card 39A, you are not permitted to do so.