Not sure if it matters, but in the 00_cultures file of "Vassal kings are dumb" there is a missing } after Swedish so all the culture seem to be inside of north_germanic. Swedish also eat the other north-germanic cultures like danish.
"2. Copy paste all folders from Vassal Kings are Dumb except Events to their HIP equivalents." Does that mean transferring them into the HIP folder and overwriting HIP's? Shouldn't the "dependencies = { "HIP - Historical Immersion Project" }" fix it or does having both of the religious and dumb king mod conflict each others as they are both referencing HIP?
In that case, would making a chain like one of them depend on the other which depend on HIP work?
Trying to see if it could work with my mod but your modded 00_cultures file contain lines that are unchanged from HIP's (logical considering you say you need to manually overwrite them). But usually, if the dependencies worked correctly then lines that are unchanged in the files (like "modifier = swedish_culture_modifier") could be safely erased from your mod (assuming you don't go and erase HIP's). It would allow then other mods to touch those unused lines.
I don't think that's correct. I checked it and everything in 00_cultures is properly bracketed; additionally everything shows up fine in game. Finally, Swedish isn't the last culture in north_germanic. And anyway I didn't touch Sweden; the only culture I added was Scots, which is in the west_germanic category; so if you have a problem with cultures that isn't related to Scots, it's vanilla HIP.
As for folder compatibility, the deal is that I know some historical stuff conflicts, probably because the game doesn't know what order to load the mods in. I don't know how to fix it and don't really bother with it since it's much easier to just copy and paste stuff to make sure. I'm not very knowledgable about how the file structure works, so. But as for changing stuff, it should be pretty simple to just edit stuff you want to mod manually.