videos counting towards mastery & assignments towards mastery

I've searched and searched, so if this is answered somewhere else, I apologize.

I teach in a rural, poverty stricken area.  Getting kids to work on a program like this can be like pulling teeth...and requiring them to do the work on their own outside school means that several kids will never do it....With that said, I'm wondering if there are ways we could make this more time efficient.

1) If I assign topics to do, can it also work towards the course mastery?  Because of the mastery challenges, these topics will be revisited (if I understand them correctly).  This way, I could assign topics that I want the kids to work on and they're getting more bang for their buck, so to say, by completing the assignment AND getting mastery credit.  

2) Are videos mandatory for course mastery?  If it's a topic that I've already taught, some of my kids won't need to watch the video.  Personally, I would rather they use their time completing the exercises/quizzes - that would show me if they've mastered the content. Watching the video does not.  They could watch the videos if they need additional support.  They will get very tired of the program, if they have to watch videos they don't need to watch.  

Again, if I've overlooked where these are answered, I'm sorry.  I just want this program to work efficiently for today's generation that don't want to do unnecessary work (just like we don't like doing extra work!!)

Thank you!