I'm not saying not to add them I'm saying keep an open mind to what may and may not be canon.
I don't think we will ever know what is canon. So for me only what is seen on the show, and even more so, only at the time when Ron Thornton and FI had control over the CGI is considered canon or whatever. If you read the articles at the B5 Scrolls, you will notice that the guys at FI really cared about bringing some logic into the B5 world, compared to the technobabble we knew from ST, down to getting the inertia of the Starfuries right and the gravity of the station itself. And even they made errors, like the Omegas firing beams out of the wrong guns and never using their missiles.
The rest I explain to myself by comparing the technological states of the different races which did play a huge role in B5. Vorlons and Shadows being the most powerful, use beams no other races use. Already here I dislike the Spitfires and Scouts not using beams but this is like it was shown. Their main helper races the Minbari and Drakh again use beams no other races use because they won't submit their advantage easily. With them I really dislike the ugly Drakh ship design and would rather have seen the much stranger looking Streib ships in their place, which (not by accident?), use blue beams as well, as did the X-Omega destroyers, which are based on Shadow tech. So far it all makes some sense to me.
EA and Narn using the same beams is logical too, and I don't think we are talking about easily replaceable colors here. I bet the FI guys wanted to differentiate the races and their technological state by their weapons. They did so regarding the engines and the artificial gravity too. Vorlons, Shadows, Minbari, Drakh and several league races all have no jet engines and supposedly artificial gravity. Centauri have the latter but classical engines, so they could be somewhere inbetween. EA and Narn have jet engines and no gravity, so it all makes sense in perspective of their development! BTW, did we ever get to see a Pak'ma'ra ship? I can't honestly remember...