I have to disagree with the concept of using a nurture program for this flow to start with. The Default program you describe will do the job for you, so there is no need at all to ...
You need to set your Default choice to Do Nothing (remove the value that is in there currently), otherwise everyone will be removed from the flow.
After that last flow step, you do...
In addition, when using urls in your program tokens, I would always advise to remove the https:// from your token and add that in front of your token when selecting the image. That...
There's two things you need to change in your add to list flow steps:
If Newsletter contains instead of is (because there could be more than one newsletter value in the field).
Se...
Creating or updating should not be different rights, but with my experience so far issues like this seem to always come back to permission levels either for the sync user or the SF...
Ah, the MSD quicksands...
The second question is the easy one to answer: No. The Person <>Lead/Contact sync is the only one that syncs in both directions, all other objects are MSD...
I would indeed be extremely careful in making changes like this and if you do, document them very carefully. As@Darshil_Shah1says, it can cause you massive headaches going forward ...