Idea variation and this mod conflicts with eachother. Can't play, and I like both mods.

What is not working? The whole game or some parts of it?

I will see what can be done.

I suppose that it will be possible to unite both this modes

Files that were changed:
/common/custom_ideas/
/common/defines/
/common/native_advancement/
/common/naval_doctrines/
/common/religions/
/common/religious_reforms/
/common/static_modifiers/
/common/subject_types/

Files that were added:
/common/advisortypes/
/common/cb_types/
/common/countries/
/common/country_tags/
/common/event_modifiers/
/common/governments/
/common/opinion_modifiers/
/common/triggered_modifiers/
/common/wargoal_types/
/decisions/
/events/
/gfx/flags/
/history/countries/
/localisation/

In order for idea variation to work with extended timeline, I have to use two of the owner's mods. This may cause a problem with trying to make them compatiable, as you'd have to look into both mods. The game doesn't work after you pick your country. Music cuts out after you start, and seconds later the game crashes.

Then turn off idea variation

Idea variation is a global mode as it overwrites defines and static modifiers so it can not be compativle with my mode.

Using Idea variation and ET patch and no crashing.

I also had no problems

Playing as Ashikaga with extended timeline mod, Development rework, and Course of Empire mods.
I annexed my a couple subjects which went as expected. Though after many revolts in vassals provinces. I annex a third vassal. The Seperatism is stuck at 15 unrest for 2 provinces and will not decrease after several years. I noticed some other provinces sometimes had this as well.

That’s not a bug. Separatism was increased from 30 to 45, so be more patient and careful, or your empire fill fall.

Their can be unrest from cultural unexceptionate, war exhaustion, overextension

What province unrest modifiers have this provinces?

Yes Im aware seperatism unrest has been increased much higher. which has worked appropriately in most provinces. However some provinces after being annexed as a vassal that has seperatism prior to being annexed. Will then get stuck at 15 seperatism unrest. And will not decrease seperatism even though it says it should decrease 1.50 per year.