I'd seen that forking chart previously and i've read tons of comments on it. Finally, I don't see clearly the credibility of this tree. Some parts are correct (mainly the ones where the source was stated by their authors), some are not.
My humble opinion is that without trustable, proven scientific base attached to them, these illustrations can't be considered more serious than speculation. So i advise to not get fooled about origins unless they are disclosed by the authors.
Or you can do your own judgement about two engines suspect to be identical by extracting detailed PV's of two engines by depth, time elapsed to reach etc on dozens of key positions and compare. This method ensures a result, maybe not 100% accurate but somehow trustable. There are many sites showing that kind of comparisons.
My assumption is that one day, as per the ongoing trends, all engines will be obliged to agree on the same move and varieties will disappear. Look at the cars. They look the same over and over unless brand style takes over performance. In chess, we don't care about style but about pure performance :-)