MADATO - what other mods have you got, for example have you downloaded the Greece mod, or Sons of the Dannenbrog? Those edit the regions.esf, which would cause the computer to complain, as it is not compatible with my startpos. If not, then I wouldn't know.
harsivo - It is very easy to change a religion, or you can add a new building thread of religious buildings for Sihks (although I'm not sure how to add the agent). I will do this over the weekend I think, because a lot of people have been requesting it.
costi - Intentional, I have heard it before. You can't do diplomacy with pirates as a major nation, so why should they be able to do it with you. There may be a way to work around it after next patch, in which CA have promised to release some of the diplomacy files for editing.
Big_Roebuc - main\startpos.esf\CAMPAIGN_STARTPOS\CAMPAIGN_PREOPEN_MAP_INFO\DATE me thinks, although it may be in a few other places as well.
main\startpos.esf\CAMPAIGN_STARTPOS\CAMPAIGN_ENV\CAMPAIGN_MODEL\CAMPAIGN_CALENDAR\DATE as well