That's really cool! Like a neat little shared universe between fan made characters. I always imagined there was a shared universe between many of the doomerboard projects like TNT, Plutonia, BTSX, JPCP, Auger Zenith and all the mods you mentioned plus many others. Glad I'm not the only one who thought about this type of thing. Imagine if they all take place in the same universe, lol.
Btw, do you have discord or something? Just curious.
The way I see it, doom modding is all about the freedom to tailor the gaming experience to one's own liking, and thinking about which doom mod characters would get along with each other can be a great expression of that freedom!
On the topic of doom mod characters, if you haven't played LossForWords' mods yet I strongly recommend them. He's got some fantastic characters goin on, as well as some fantastic weapon mechanics, and if you're keen on the ol DBPs I know at least 3 of his weaponsets fit certain DBP themes to a T. https://lossforwords-atmo69.itch.io/