From what I have seen they all seem to sell for about $50 each, except for Seabreeze who seems to be more htf (for whatever reason!) Maybe slightly higher.
High Tide and Wave jumper with faded hair will affect value slightly, and the 3 white coloured ladies seem prone to yellowing, discolouring, and age spots.. My whitecap is in gorgeous condition but she was bought as new by a collector and never played with, I'm nervous to have her to be honest I dread the day she finally gets her spots!
Seaponies were mostly played with anyway so I would say don't be worrying too much about flaws!
and I have to ask the cheeky question, will you be selling them? I still need a couple, I've held out for years wanting to buy them with shell but I've come to accept replicas