I assume by your first question that you mean that you have the program directly connected to SFDC. Once the sync is initially done, there are no further updates sent down so you will have to add that progression status manually to both the MKTO channel as well as the SFDC campaign. This is a great article explaining how and what updates: https://community.marketo.com/MarketoTutorial?id=kA250000000KytlCAC
The article should answer both your 2nd and 3rd questions as well.
As for the fourth question, SFDC does not retain an order to the statuses - so if you swapped the progression of steps in MKTO, it would not need to re-order the data in SFDC. However, unless you weigh the progression steps either the same, you may run into issues having the progressions re-order. Progression steps can take you forward, side to side, but never backwards. SFDC does not have any limitation like that.
Hope this helps!
Helpful, but can you please refresh the link to the answers for Question 2/3. It's linking to the homepage. Thank you