Most of what you are asking for is confidential and restricted internal information. What we can give you covers most of the questions, but not the statistics.
We can confirm that the World Map movement is fully automated and occurs every Monday. This action removes inactive players as well as moves active players who have the option to move selected in their game settings. Therefore the last 'sweep' was August 30th and is going on currently for this weeks changes, as it is already Monday here.
To move to a new spot on the map, the spot needs to have identical Boosted Goods, the same amount of completed Provinces, as well as the same amount of Province Types completed (so no Relic changes). This is why it can take time for an identical position to become available due to the precision needed.
Depending on the account inactivity depends on how quickly these are deleted, but we do give at least 30 days before we will make the city deletions on played a...