What is the answer to the atheists' argument concerning the problem of evil, specifically the suffering of the innocent, animals, and children? And does Allah lack our creation to manifest His attributes, and does He need to manifest them, is He not self-sufficient above all things?

Allah is independent of His creation, and His attributes are perfect and eternal, neither increasing with their creation nor decreasing. He does not need to manifest His attributes; rather, creation is in need of deducing them. Allah's perfection is inherent and does not require a completer. Divine commandments are for the benefit of humankind and the organization of their lives, not out of any divine need.