Why are there escorts leading the chosson and kalla to the chupa
The reason is that being that the choson (and kallah) are like a king (and queen), and since it is the norm for a king to be surrounded by people so too, when they go to the chupah they are surrounded by people.
As a side point the minhag is that the two escorts carry candles. The reason for this is because, a male has 248 organs and a female 252, which together equals 500. The gematria of “ner” is 250, and two candles equals 500. Also the gematria of “pru urevu”, also equals 500.
Tasbetz, Mateh Moshe vol. 3 Seder Hachnosas Kallah 2.