I'm sure it was physically possible. I doubt the laws of physics would have prevented a few European guys setting up camp somewhere in Angola.
*And Hearts of Iron also discredits any ahistorical attempt at anything in Victoria II. It's a seperate game. It isn't relevant.
Between the tons of hostile natives (more so than the Americas), deadly diseases (much more so than the Americas), lack of any resources to use the European form of agriculture(which was incredibly easy in the Americas), much nastier wildlife, lack of profit from such a colony (which was the point in colonies), and the length of time pre-Industrial travel takes, I'd say yes. It is impossible.
The coastline and South Africa are a different story though. My main gripes are the fact that Europeans colonize far into West Africa and how large the provinces are when they should be tiny coastal provinces, not much larger than a city.
There is no way that went over your head.
Victoria 2 represents historically accurate technological ability. Borders do not matter, the potential for these borders had to become real are what matters.
If Germany colonizes the Mali in V2, that was a possibility considering they had the money and technology to do it.
If Portugal colonizes Mali in EU4, that was impossible. That could not have happened and should be reflected in gameplay.