Cleon
Legend
It looks like a variant wight with a variation on the following ability...
Beguiling Song (Su): A rusalka can attempt to beguile creatures with its song. The rusalka sings, targeting a single creature it can see within 300 feet of her body of water (see water symbiosis, below). This is a sonic, mind-affecting ability, and the creature must be able to hear the rusalka for it to take effect. The targeted creature must make a DC 17 Will saving throw. If the save is successful, that creature cannot be affected by that rusalka's song for one day.*SNIP*
They remind me more of a Vampire with the claws and teeth of a ghoul - the life-feeding, charm, immunity to non-magical weapons and human appearance all say "Vampire" to me
I'm not seeing where the beguiling song comes from, it just looks like a standard charm to me. They may entice victims with their charm power, but there's no mention of it being a harpy-like song, and how would it allow them to convince people to find & bury their remains?
Despite them having some vampire-like traits I would prefer to do them as a base creature rather than a template.
Anyway, these things look pretty straightforward.
They're 9 HD Medium Undead, pretty obviously.
I'm thinking they are not incorporeal, despite having their remains separate from their bodies and becoming Wraiths if they don't feed enough. They're in a bit of a grey area, corporeality wise.
A Ghast's ability scores strike me as good fit:
Ghast: Str 17, Dex 17, Con -, Int 13, Wis 14, Cha 16. Natural Armour +4.
An AD&D Ghast has AC4, just like an Amiq Rasol, so I wouldn't fiddle with the NA to make its 3E armour class exactly match AC16.
These things are fast (18" swim 9"), so Speed: 40 ft., swim 20 ft.
Two 1d4 claws and a 1d6 bite.
Their SA/SQs don't look very complicated.
+2 weapons to hit
-> DR 10/magic and silver, like a vampire? Maybe bump it up to DR 15, since vampires only need +1 weapons to hit in AD&D.
Beguilement
-> I'd just make it a 3/day charm with a long range.
Living Appearance
-> A permanent alter self type effect? I don't think it's a glamer like disguise self. There's no mention that anti-illusion spells counter it.
Energy Drain
-> 1 negative level per bite, with a note about them wraithifying if they starve.