Will the LG videos for PTs 72-74 be added to the mobile app at some point?

On your test ticket it says earplugs are not allowed, so use at your own risk! I would recommend using ways that you know 100% will be allowed on test day.

They are not any harder or easier than any other test. LSAC just keeps tests undisclosed in case they need material for make up tests and international versions.