Undead fey isn't a bad idea, actually. And, yes, I like those three abilities.
Okay, I'll revise the Special Abilities list to include those 3 powers.
I'll also modify the Horrifying Appearance so it doesn't include manifestation - since you don't like it


- and I'll do a proposal for invisibility while I'm at it.
Finally, I'd like to curb Deathly Shriek so it only works at night against creatures which don't have any anti-evil spells on them.
Revising...
Eldritch Glow (Su): A galley beggar can surround itself with an eerie light with the same effects as the
faerie fire spell. This light allows the galley beggar to use its frightful appearance power in conditions of darkness. Galley beggars can create or extinguish their eldritch glow as a free action.
Deathly Shriek (Su): Once per day, a galley beggar can utter a horrifying scream.
A galley beggar's deathly shriek can not harm any creature that is in daylight (natural or from a daylight spell) or that is protected by a consecrate, magic circle against evil, protection from evil or similar spell. Otherwise, any living creature within 60 feet that hears this deathly shriek must succeed on a DC 14 Fortitude save or immediately take 1d4 points of Strength damage, 1d4 points of Dexterity damage, and 1d4 points of Constitution damage. A creature that successfully saves against this effect cannot be affected by the same galley beggar's deathly shriek for 24 hours. The save DC is Charisma-based.
Frightful Appearance (Su): A galley beggar can unsettle foes with its mere presence. The ability takes effect automatically whenever the beggar attacks, charges,
or suddenly appears (usually by dropping its greater invisibility). Creatures within a radius of 60 feet are subject to the effect unless they have more HD than the galley beggar. A potentially affected creature that succeeds on a DC 14 Will save remains immune to that dragon’s frightful presence for 24 hours. On a failure, creatures with up to half the beggar's HD become panicked for 4d6 rounds, while those with more HD become shaken for 4d6 rounds. The save DC is Charisma-based.
Ghostly Hand (Su): A galley beggar can telekinetically move small objects as by the
mage hand spell, except its ghostly hand has a range of touch.
Greater Invisibility (Su): A galley beggar is normally invisible. A galley beggar can suppress its invisibility as a free action, but can not become visible in daylight (natural or from the
daylight spell). An invisible galley beggar can not use its frightful appearance special attack on creatures unable to see invisible creatures. Galley beggars can resume their
greater invisibility as a free action.
Turn Resistance (Ex): A galley beggar has +2 turn resistance.