Answering your questions in reverse order here...
First, the easy one -- I don't think there's any special connection between Unique Ability / Critical Flaw and Catalyst / Inhibitor.
There is a subtle interaction between MC Unique Ability and MC Critical Flaw, depending on Growth of Stop vs. Start. See the last part of the definition here.
If possible, you should show the Unique Abilities and Critical Flaws at least a few times in the story (maybe once per Act), so that when they come up at or near the climax, they don't seem to be out of the blue. Personally, I don't think it's critical to show the CF always messing up the UA; earlier in the story I think the MC can get a nice little "win" from their UA. (In this case, perhaps, you're just foreshadowing a characteristic that will later have an impact on the overall story.)
Finally, for Catalyst and Inhibitor I would think more about speeding or slowing the pace towards resolution -- you used the word conclusion and that's pretty good too. Generally I think the Catalyst increases necessary conflict and the Inhibitor reduces it, perhaps leading to sections of the story with less conflict (in that throughline). By "necessary" I mean, the type of conflict that is necessary for the throughline's difficulties to be addressed.