I may be wrong but I think that Catholic Boy is being a bit over-rated, mainly on the strength of his Travers win. That race came up much slower than expected and many of the top contenders did not run their best races. He tracked a much slower pace than Diversity set in the JCGC and, while he did beat Mendelssohn in that race, Mendy's performance in the JCGC indicates that he is cycling back to the freakishly fast figure he set in the U.A.E. Derby and the BC Classic is the race he has been pointed to all along.
I would not throw out Diversity either due to the JCGC. That performance should get a line put through it due to the suicidal pace he set. Of course if that was because he cannot be rated, rather than a rider pace error, then he could be vulnerable in the BC Classic. That might be true for Mendy as well but a lot depends on what the pace and strategies will be in the Classic.