Regarding your question about the Brahmajyoti, it is explained in Bhagavad-gita that the impersonal Brahman effulgence is emanating from Bhagavan, the Supreme Personality of Godhead. The brahmajyoti is just like the sunlight, which emanates from the Sun God: Because the sunlight has no personal form, this does not mean that the Sun God has become impersonal.
Letter to Bhadra Bardhan, 4 December, 1969