Ok, lets see... where to begin...
You have what appears to be an "oklahoma salmander" AKA "eurycea tyerensis. These are quite awesome little guys, and there is a lot to know about them. The unique thing about this species is that some of them morph and some do not, according to their natural environment.
Considering you said they come from a streambed that dries up in the summer, I would have to assume that so long as their environment mimics that of their natural habitat, there is a good chance they could still morph. I found a good article about them here: http://images.google.com/imgres?imgu...icial%26sa%3DN
The first advice I have to give is to get the crayfish out of the tank asap!!! The crayfish will eat the salamanders. If you provide the salamanders with an aquatic envrionment year round, there is a chance they won't morph, and then the care needs would be the same as the axlotl. Temp should be in the low to mid 70's, feedings should consist of small worms (black worms work well) and small crickets for the primary diet. Water quality will be important, so a good filter or a lot of regular water changes are called for to ensure that water params are always good. When keeping something like this in an aquarium, remember that if ammonia or nitrites are present at any point, they can burn the skin and cause open sores to develop. Also, with regard to nitrate levels... if they are higher than 40 - 60 for a long period of time, the pH will drop, also causing large open sores on the body of your salamanders. These sores tend to get infected very quickly, and the animals usually fall victim to secondary infections which are very hard to try to treat. A good filter AND lots of water changes will help the most.
I would keep their water level at about 1/2 in the 10 gallon tank, with at least 1 large rock that sticks up out of the water enough for them to climb out if they morph. Keep a close eye on them. Most salamanders will morph at much smaller sizes than 4 inches... so these may be mature and not going to morph at all. If you don't see that they lose the gills (the "ear tufts) over the next 2 - 3 months, it is safe to assume they won't morph at all, and care should then be given for fully aquatic their entire lives.
If you have other questions or need help, let me know and I'll do what I can. One other resource for you is to contact the local DNR in your area, get the pamphlets and books they hand out which list all of the native species of amphibians and reptiles in that state. This will give you much more detailed information than I can provide here in a single post.
Either way, move those crayfish out asap for the sake of the salamanders, and don't mix the salamanders with any other species, such as axlotls or newts... they tend to be canibalistic to an extreme and will eat each other if size differences allow for it.
I hope this helps!