Choosing pickups is bloody hard. I've had two sets from Bareknuckle now and I go through the tortures of hell every time yet I know where the big problem lies - I overthink it. The problem is that the more I overthink it, the harder the decision becomes because I get bogged down in tiny differences when I should just get on with it. I mention this because I get the impression the same thing is starting to happen to you and believe me, I do sympathise.
You've found the sound you want in the Pearly Gates and you described it as 'perfect' so I guess one option is to buy the Pearly Gates. Of course, like me, you know Bareknuckle pickups are better and that being the case, Stormy Mondays and PG Blues are the obvious equivilants, except that it's never that simple. What people are telling you about the Mules and Abraxas is absolutely true and as evidence I will quote Tim:
"Alnico IV is probably the best vintage tone IMHO(for humbuckers) and along with II and III was used in the earliest PAFs-this is a fact and not myth as we've had them analysed and a collegue of mine has also seen original Gibson purchase orders that clearly state AIV bar stock being purchased.The tone of AIV is balanced and extremely organic, it produces the most authentic vintage tone and sits better in slightly hotter vintage winds than AII which tends to get very soft in the bass and highs if used incorrectly."
What's more, Tim will practice what he preaches because he uses Alnico IV pickups extensively himself. I've played Mules myself and they are incredible pickups that will serve you very well indeed. It's also clear from the posts here, made by those who know the Abraxas well, that the Abraxas will serve you equally well and possibly more so. The Mules are extremely versatile, going from Blues to Rock/Metal and if the Abraxas is basically a hotter Mule, there is no reason to doubt it will do all that the Mule can and possibly a bit more. They'll both work beautifully and you'll have no complaints. If it was me, I'd go with the Abraxas set because I think they'll give that bit more versatility and I think the EQ suggests they'll be well balanced in your guitar. Hell, I'm saving for a mahogany guitar just to put Mules in it and even I'm thinking that an Abraxas set might be a better option!