Dragonman...most of your questions were answered in my first post. As to where did they get beads. Beads were trade items brought in by the French and English traders.
Thread was not introduced until the 1860's so most beadwork before then was sinew sewn. Even after thread was introduced sinew was the main sewing material for the Plains tribes even into the early 1900's.
Fusizoli...Indian symbolism is hard to learn about because many of the symbols were only known to the owner of the symbol. The few symbols that are know can be found in various books. Here are some known symbols...tornado/ whirlwind, morning star, dragonfly, horse track, buffalo and bear track and the four winds. Each symbol could have various meaning to the owners. For example four horse hoof tracks could mean four stolen ponies, a bear track could mean bear killed or the owner had bear medicine...etc...etc. I would need a book to discuss all the Indian Symbolism possibalities.
Eric