It shouldn't, in the save I tested I had the Wapal Indulgence, Red Dossier, Oblivion Parasite, Dreamochrome, Crime Machine, and Melotine Patch all active.
As long as your "endingScore" stat is 15 or higher then you should be able to choose any ending you qualify for. The Black Book will hint which endings are available during a run with either an empty box or a checked box. Earlier when you said the Black Book stated you were eligible for 6 endings, were the boxes empty or checked? An empty box means you got the first step to that ending but haven't completed the requirements.
Another thing that's specific to the Wedding Bells endings is the Black Book will hint at marriage but say something like "I'll need a ring". Also if your evil score is too high, you get locked out of marrying anyone but the jealous wife.
If you only qualify for one ending then the game will skip the part where you choose which ending you want because there is only one option to choose from, even if you have an "endingScore" of 15 or higher.