Are the attributes included in the appellation of "Allah" only the essential attributes, or both the essential and volitional attributes together? Does this include Allah's speech, mercy, knowledge, power, and descent? And what is meant by "Allah is one God with His names and attributes, and all His names and attributes are included in the appellation of Allah"?

The name "Allah" is a proper noun for the Being described by essential and active attributes, not for a being devoid of them. It is the broadest and most comprehensive of names in meaning. Thus, when a Muslim says, "Allah is my Lord," it means that his Lord is the magnificent Being characterized by knowledge, speech, mercy, face, hands, and other attributes. The names of Allah are both proper nouns and descriptions, and His glorious attributes are included in the meaning of His name. He is the gatherer of all perfect attributes and majestic descriptions, and all the Beautiful Names are encompassed within Him.