here are my ideas for enemies:
Undead Tyrant (uses multiple non-magical weapons
Demon Stump (lvl 40-45)
Undead Warlock (uses voodoo staff)
Navy Bomber (throws Grenades - i cant think off any other name)
Navy Bayoneteer (or whatever they hold that shoots stuff)
and an undead person who has a handcannon
add the race of undead half flesh zombie (non-skeletal) creatures that appear in Isla Cruces in the At World's End game for ps2 on isla cruces.
introduce the shadow army of the shadow lord (in the very far future)
Hades' guardians sent from Davy jones locker to hunt down undead (and pirates in their way)
Calypso's creatures (in the very far future as the previous one)
Queen Wasp
Steel Teeth Alligator
Sea Serpents
Giant Squids
Giant Sharks
Scyllas
Hydras (in islands)

davy jones crew must have the other people who come on his ship like the hammerhead shark guy.
IF new ship types are introduced :
EITC Mammoth
EITC ?Humongosaur? (jk hehe)
Navy Stallion
EITC Pharaoh
Navy Rottweiler
Chaos Emperor (undead)
Navy Grey Steed
Doom Python
Damned Necromancer
well its hard to give the names so congratulations to those who did

Heres some more.
Navy Commander

Rootful Stump

Undead Harbinger


Humungus Aligator

Moon Jelly

Jelly

Man-O-War


This is a mythical creature i made up..

Its a 1000 year old Human-Squid-Shark-Fish,called Gygrojus.

EITC Lutinet

Not very full of ideas...


Undead Thrall Pirate Lord


Anchor Body (A person from Davy Jones crew that has a anchor on his back)

Undead Abassador


Miguel (A spanish captain boss)

Undead Veteran


Sharkbait (A person from Davy Jones crew, he has a shark head pulled over his head with his head in the mouth.)