What should a girl do with colored clothes and non-Sharia-compliant shoes after becoming religiously committed, and would giving them to others be considered assisting in sin?

It is not permissible to destroy colorful clothes and high-heeled shoes if they can be used for purposes other than what is forbidden. They can be gifted or sold to someone who will not use them for forbidden purposes, or kept for legitimate use. It is permissible to give them to a married sister unless it is known that she will use them in a forbidden manner; otherwise, it is not permissible, because that would be assisting in sin.