Hi,
Your P.chrysurus is not rare, it is just endemic to the east coast of Africa and being imported mainly from Kenya.
If you dont mind me saying, I think you're about to get ripped off if you pay 500 bucks for this fish, unless it is over a foot, and then they can blame the freight charges maybe.
chrysurus like most Pomacanthus spp. can be seen in Reef aquariums, main problem is that you cant really generalize all as one, while you see a 3"specimen at your friend's tank touching no clams or Acros, you can buy an identical specimen in the shop that will nip at about everything after a week it is in the tank.
From the species you gave:
Majestic :better chance
Queen: dont even try
Emperor:great success next to big failures
Passer: dont think about it
Mac:I had nothing but nippers, I heard of ppl who had success
Asfur:I have one right now, waz excellent never touched anything till a month ago he dcided to eat a small clam, I cant say what was the situation of this clam as I was a broad, now I watch him very carefully.
If you wanna be on the safe sidewhile keeping Angels go for Genicathus spp. these are great reef fish.
If you're planning to spend few Franklins, you might wanna do it on a safer target as far as your clams goes, maybe try a C.joculator, super nice fish.