A little more info would be helpful. Is this a clay studio or a paint-your-own facility? Assuming your kiln is electric, what temps/cones are you going to be firing to? You say the kiln needs "love"--what exactly do you mean & what kind of kiln is it? You should be able to re-hydrate the clay but you need to know what they are--low, mid, or high fire bodies? I'd definitely have conversations with the glaze distributors for products that old...make a list from the label info so you can tell them exactly what you have. What a project-sounds like a great opportunity.