How is the world outside of Crusader Kings II's boundaries generated? Does it default to the standard EU4 1444 set-up?
It depends. Most of the time, yes, it will probably be the default. But there are some special events in Crusader Kings II that changes this...
Other than the Mongols, what stuff from Crusader Kings II "spills out" onto the larger EU4 map? Is there a hard boundary to how far it can spill?
There are the Timurids who can start to invade [in CK2's late game]. They start with some provinces outside of visible Europe. These two will be joined together. The same for the Golden Horde.
Are heresies for each Crusader Kings II religion converted over? If my entire Persian empire was Manichean, or I had an Iconoclast ERE, does that transfer?
The religion system in Europa Universalis IV is totally different from Crusader Kings II, where each heresy is its own proper religion. Europa Universalis IV doesn't support that, so unfortunately, you will get the parent religion after conversion.
Do converted cultures and religions get any unique CBs in EUIV?
Does Muslim decadence carry over in any way?
Do claims transfer over?
Some of the claims do transfer over, yes.
Can West/East Francia ever become France and Germany, or are they stuck with those names if they exist at the time the Crusader Kings II save was exported?
They will be stuck as West/East Francia in Europa Universalis IV.
You mentioned that if a realm has Minimum Crown Authority in CK2, the direct vassals will spawn as independent relams with vassalage contracts to their liege in EU4. How is multi-tiered vassalage handled? Is only the first level of vassals under each ruler relevant?
Only the direct vassals of the ruler are considered. But for Holy Roman Empire, every level of vassals is considered to take full advantage of the HRE mechanics in Europa Universalis IV.
You mentioned that importing a game with the CK2 Sunset Invasion DLC will spawn a huge Aztec Empire in North America. What flags a Crusader Kings II save as a "Sunset Invasion universe" game? Is it just having the mod checked when you export the save, or does the event actually have to fire?
Just have to have the DLC loaded when exporting!
How far ahead is the Aztec/Inca alternate history tech group in an imported Sunset Invasion game? Do they get new ideas separate from the historical Inca/Aztecs?
This is one of the things we want people to play and find out.
Do the other fictional North American states mentioned in Sunset Invasion exist in an imported game? Like, could I play as the Aztecs, and have a rebellion to restore the Shoshone/Iriquois free states? Would they then be part of the super Aztec/Inca tech group?
Are there any plans to port Europa Universalis IV saves forward to Paradox Development Studio games set later down the timeline?
Not at the moment. One step at a time.
Thanks to Henrik for clearing up these details for us. Watch for more on Europa Universalis IV and the save game converter in the coming weeks.