Welcome to the Cafe.
I take it that you are asking about how to use the EDITOR
The EDITOR works on the characteristics of the MAP
The second half of creating a scenario is scripting events
. So far as I recall, there is NO event code to activate or repeat an EDICT.
Therefore, the answer to your question about the edicts 'Papal Visit' and 'Open the Jails' is NO, there is no way to change the conditions on EDICTS.
Building additional Archeological Sites causes no problems in game play. However, you may find some problems with the building routine - some people report that getting the building placed causes some unwanted land leveling.