I can't answer all of your questions, but I bet others can and probably will! Tracey is very knowledgable, and hopefully will jump in.
I have not done this cleanse before. I have been on a journey to improve my diet and health for several reasons - I'm 46, reasonably healthy and active, but overweight and probably full of toxins from a few decades of eating a typical american diet. My greatest health challenges recently have been back pain and sciatica, to the extent that I was on steroids and muscle relaxers for weeks, and have since found chiropractic care and yoga to be very helpful. I've been practicing yoga on and off since '98, but very regularly for the past 6 months.
My more long-term motivation is that my father and grandmother both declined with Alzheimers prior to their respective deaths. My dad, in particular, went through kidney deterioration and had all kinds of health issues which, in retrospect, seem to point to significant toxicity. I don't want to follow that path, and I believe this is a way to prepare myself to move toward a vegan and ultimately raw diet. I plan to do a liver cleanse after I finish the MC.
I am not doing the salt flushes. I became familiar with psyllium from following the Fat Flush program (a book I've not seen referenced on this forum, yet), and when I learned about the Psyllium and Bentonite combos many MCers are using rather than the salt drink, I chose to go that route. So, I'm drinking the lemonade, taking a cup of lax tea at bedtime, and drinking the P&B shakes upon rising and before bed. I also tried a cup of peppermint tea this evening, and that was a nice change of pace.
I have read many diverse posts about the salt flush - lots of people have challenges with them, so it could be that you'll need to work through that and decide which way to go.
Sounds like if you need to move alot, you should certainly do so! Too many of us don't move enough!
I hope some of this helps you, but I am certainly a novice here.