No soap does not use bacteria in its making. One of the objectives of soap using is to get rid of bacteria.
Use antibacterial soap, and scrub off the hair dye. If you dye your hair again, I recommend putting Vaseline on your cuticles and wearing disposable plastic gloves.
making soaps and detergrants
Yes, but there are more preferred sources of soap-making lye.
I think you mean soba noodles, and yes, they are made of soap. ~ Soba noodles are not made of soap. Soba noodles are a Japanese edible noodle made from wheat and resemble spaghetti. Soap noodles however are already soap, which has been shredded or ground and pushed through an extruder dye and cut into "noodles". Crafter will use pre-made soap noodles to make bars of soap, when they may not be interested in making their own soap from scratch. Soap noodles as a base for making bar soap, are generally different from a melt & pour "glycerine" soap base, but both will allow a crafter to get creating and produce soap without the danger of working directly with lye.
no
it depends on the brand of soap and some don't use any chemical's
The main ingredient in soap making believe it or not is Oil, Sometimes Olive oil. There are different ingredient that always go in soap but the one they always seem to use it oil.
yes it is safe to use in soap making. It's basically a glue of some kind. Sometimes even egg white and then just colorant. I use it in my soaps and it works fine.
glycerine
Soap noodles are essentially already soap, which has been shredded or ground and pushed through an extruder dye and cut into "noodles".
Yes.