1. Yes. To simulate rope climbing you can stagger the towel ends that you hold onto if you want.
2. Shrug. Not sure about that but if you wanted to add 1x5 a la SS one day a week I'm sure it would be fine. Just do it the day before you have a rest break or two after your workout is over.
3. As long as it's not going to interfere too much with your recovery.. which it shouldn't. You should be fine.