Hello Costin
1. My apologies for the trouble! Unfortunately, if you add a marketing list to a nurture while the nurture is already running, any members already in the marketing list at the time will not be recognized by the nurture. However, any members added to the list after the list is added to the nurture would be recognized. As such, you can circumvent this issue by adding a blank list to the nurture, then adding the members of your existing list to the blank list.
2. The nurture is checking for any clicks that occur during this time, not just clicks on the nurture email that was most recently sent. If any clicks are recorded for any email sent to this person via ClickDimensions, that will count as a positive for the "has the person clicked?" check.