Yes, both Klehss and Celerea are available. To get Klehss the octopus pirate you currently have to enter Debug mode (Left Shift, Right Enter, F2) and press F12 during the revival cutscene when you first revive her. (then middle-click to restore focus I think). My best guess is to get the Combo meter to 100 before defeating them, then they might be available for revival… unsure. If you feel cheaty or just tired, tapping 1 on the NumPad to the right will give you 10 Combo a tap, and M will insta-kill the opponent.
After I beat the game, for some reason she re-appeared in my list of revivals. Be aware that if you revive her without using the f12 technique you will be reset back to the start of Biscotti… along with all revivals after that storywise getting locked up.
So they have to be released again. oh and also if you don’t use the f12 you won’t get Klehss again, so it’s like double bad.
Noticed the revive reset. But i think that avoids the girls which are already in your party (?), got my ghost and mushroom girls saved like that.
Eh, even if revive reset means another shard farming for reviving everyone all over again, then that's isn't a big deal with ghost's orbitals attack.
Edit: Fixed almost everything. Just like i said in the first comment, because i was flying through cutscenes aka game progress by F9, my game stuck at 33 cutscene (was too lazy to find the revive back in the day so was using a scripted one). Got back to 43th and now missing skeletons are back. Now i get what you were talking about Klehss and F12.