I’m thinking theme/plot wise, not mechanics (though I understand getting them fire is a BIG help)... obviously y’all are good enough DMs to make your PC clerics feel like their faith matters, even if they pick some Azlanti rando, but which deity selection would make your job easiest? What’s there in the writing?
Wadjet? Abadar? Ra?
Nethys would be really interesting for the end of book 1 and for the first half of book 3.
My group had a paladin of Anubis, which was super appropriate and lead to some great moments / encounters throughout the entire AP.
Pharasma, but she's a hard one to get interest in for my group.
My only fear with both Anubis and Pharasma, which otherwise do both seem like perfect fits, is the former finds it ANATHEMA to: “desecrate a corpse, rob a tomb, trap a soul,” while Pharasma’s definition of ANATHEMA is: “create undead, desecrate a corpse, rob a tomb.”
Yeah, you could do some ethical self-justification, but much of the plot early on is about taking things of inherent value from tombs and assigning them market value, so... I think Nethys is winning for me now. Although arguably he requires a lot of adaptation as well (no spoilers).
The first book of the Adventure Path addresses that exact concern. See "The Politics of Tomb Robbing" sidebar on page 9.
The player that was the paladin of Anubis never felt like they were breaking Anubis's code.
One of my players is a Paladin of Osiris, and I've found it very rewarding to engage with the lore of Osiris and how that intermingles with the Golarion status quo. Osiris was a judge of the dead, but Pharasma takes that role, so I've introduced an NPC priest of Osiris who is her mentor and who represents how the worship of Osiris has been assimilated into the Grand Mausoleum, and not everyone is necessarily happy about it - there are Pharasmins who look down their noses at them, and Osirans who resent their god being eclipsed. In my setting Osiris does still judge the souls of those remaining faithful, due to an ancient bargain struck between Isis and Pharasma so Isis could resurrect Osiris. It also sets up a dichotomy between Osiris as a patron of at least part of the party, and Set, whose mortal worshipper is the Final Boss and whose henchmen and worshippers in turn follow his will.
As someone who is currently playing a paladin (2) / Cleric (Everything else) of Anubis, we justified it in the first two books with an amusing work around. The church of Pharasma was allowed to oversee the looting of the tombs, but able to enforce rules on it from afar. Rashida, my character, was essentially on loan from the Cult of Anubis to act as a man on the inside. Smooth things over, and keep an eye out for others breaking the rules. Rashida doesn't take anything from the tombs the party has come across, only taking from the bodies of those who he has killed for doing so. (Or, when the guardians of said tombs specifically offer things as a reward for his assistance).
Anubis's followers, in our world, essentially work as a specialized task force that the Church of Pharasma can call upon if they need it. Since Anubis has left along with the others, but his teachings remain, his Cult is incredibly small in number. It has been incredibly rewarding to play as a follower of Anubis, and while I'm probably late to the party here? I think you'd also have a blast.
(We also have a Cultist of Wadjet among our party. The Old Gods be praised!)