Sandalphon does not sound like the other names in this collection, and that is not an accident of transmission. Almost every angel here ends in the divine element el. Sandalphon does not, and the name is not Hebrew at all. It is generally taken as Greek, most often from a compound meaning co-brother or fellow-brother.
That reading matters because of the tradition it supports. Sandalphon is regularly paired with Metatron, and the pairing has a specific content: Metatron is Enoch taken up and transformed, and Sandalphon is Elijah taken up in the whirlwind. Two men who did not die, made into angels. A word meaning brother is exactly the word such a pair would need.
The Talmud gives him one of the most physically striking descriptions in the whole literature. At Hagigah 13b an angel is described standing on the earth with his head reaching the living creatures, taller than his fellows by a journey of five hundred years, and the passage names him Sandalphon. Alongside that stands the tradition that he gathers the prayers of Israel and weaves them into crowns for the divine head, which is a different image entirely and a gentler one.
Malkuth, where the table places him, is the kingdom, the tenth sephirah, the material world itself, and the only sphere with no planet in the classical set.
The arrangement closes the diagram at both ends with human beings. A man who was taken up stands at the crown, and another stands at the foot, in the world the rest of us are still in.