Alright, spoiler alert, so please don't read this unless you really just want to find the ghosts.
I was helped by Koyori to locate the 20 ghosts needed...
PLEASE NOTE that the ghosts MAY attack you and are level 42 DANCERS. Thus magic does not work on them too well.
Speeding Ticket would come in handy, a LOT.
So, without further ado, here is the list of coordinates of the 20 Ghosts on the East Sea plains.
X Y
109 309
253 281
163 342
195 395
249 227
181 426
293 182
143 474
251 141
246 505
358 563
505 250
388 487
504 484
456 530
421 354
380 424
94 509
518 537
*EDIT*
Apologies, I did not realize one of them was a double... so we only have 19 ghosts, we have yet one more to find.
Verbal Locations
-There are Three Ghosts in the East Sea port, one at the entrance, one inside hiding in the cluster of houses, one on the port.
-There is one just south of the World Mirror, hiding behind a Tree.
-One inside the Cemetery.
-Two on the land jutting out in the north, one the farthest point north, another near the lighthouse.
-Two in the mid-south section, one at the entrance to the small path to the gate, and one at the gate.
-Two on the way to Blakatoa, one deep inside near the Marshall, one next to the Lily Quest.
-One near the Lovers Quest House.
