I don't think I'm the best person to address most of these questions as I am not a current student, however there is one thing that I wish I had known prior to my interview day as I also wanted the option of attending lectures but not being restricted to mandatory attendance. During my interview day, I learned the different pathways do not always learn things in the same sequence/time frame. So while you are permitted to attend lectures while in another pathway, the material covered in lecture may not match up with the content you're currently responsible for. Some of the current students I met mentioned that the professors are generally very accommodating and may be willing to send you the powerpoint for the lecture on a given topic, though, if you are struggling in an area. I hope this helps a bit!