Hello Adam,
I have dove the Cooper maybe 100 times.
If you visit my social group named the "Charleston SC Scuba Club", you will find quite a bit of information (and video) on diving the Cooper River and areas around Charleston SC. The link is below. If you need advice on hotels, I can advise you in that area. I have quite a few of the river dive boat operations listed with links to the websites.
Diving for teeth is addictive. I can't explain it. It just is. I found many years ago that diving for teeth and treasures is NOT about diving. It becomes about the people and the obsessions for finding stuff.
Diving black water is creepy at first. What you find is that once you get to the bottom and lay on the bottom with your powerful flashlight, you start to calm down. Laying on the bottom has a significant calming effect. This works in the ocean also.
A 3mm suit if fine for the summer months. A 5mm suit works for the late fall and very early spring. The guys from the northern states bring drysuits.
During the colder months a hood, gloves, and warm water poured into the suit helps quite a bit.
Some people weight themselves a little heavier than usual. If the current is slow, this is unnecessary. Sometimes it helps to carry something (like a large screwdriver) to stick into the bottom to hold you in one place. Again, this depends on the current.
Lighting is a big deal when diving black water. Take many lights. The more powerful the better. Take backups and backup batteries.
Any basic BC and regulator are fine. Nothing special needed.
Stay in the gravel beds. Work the gravel beds. Look for gray, pasty, clay. Look for large fragments of bone and tooth. Stay in front of the boat so you can float back to it upon surfacing.
The teeth in the photo are teeth I found in the Cooper River. I found the one on the right this past summer. The one on the left I found a few years back. It is what they call a rare copper colored Angustiden. It has quality and value to a collector of around $450