Following is a primer on dyes so that you can create those bear with coats of many colours.
Intensity varies with the temperature of the bath and length of time submerged.
To make sure you have enough fabric, draw your bear on the material before dyeing it. The most important part of your dye job is to end up with a colourfast product. Wash a piece in hot water, then iron it against a white cloth with a very hot iron. If it does not bleed it's colourfast. Leave a piece of dyed material in direct sunlight for about 3 weeks to test for fading.