Hn1 - you've really never read that EBJD are a generally weaker strain and less aggressive? I appreciate your personal observations, but I have heard otherwise from many owners. My LFS actually stopped carrying them because they were constantly getting beat up by the holding tankmates (regular JD, GT and FM) and they also had a high mortality rate around 3 - 5 inches for no apparent reason.
I wouldn't recommend them either in the scenario here, but saying they are "just a color variant" is a bold statement.
I've read it anecdotally, but my personal observations haven't proved it and I've read a lot of things online with varying degrees of fact. I have never kept a regular with an EB so I can't make a direct comparison of two in the same tank. An EB in a tank with "dithers" is just as boisterous as a regular JD IME though. Based on EBs being selectively line bred to the Nth degree, they do tend to be weaker fish in general.