You have not heard buddha say that ? :
http://www.accesstoinsight.org/tipitaka/sn/sn22/sn22.097.than.html
I feel you might believe in the Thanissaro or other thai forest taditions ideas of consciousness “luminous all around” in nibbana based on twisting 2 poetic verses from DN, disregarding hundreds of suttas from SN. A proper contemplation of SN chapter 2,3,4 (and by that I mean 3-4 months) will dispell that idea.
If this is the case, that would also explain the description of stream entry as having to do with ethics and not with properly understanding the non-existence of a self.
As for Thanissaro idea of “Buddha refused to answer if a self exists or not” - that is explained in the very sutta that he uses to make a case for such a thing. At the end of the sutta we see Buddha explain he did not answer like that to the bhramin so that he won’t become confused that there was a self but not the self is no more. In Buddha teachings, there was never a self to begin with. Only the opinion of a self existing. Just like Freud ideas about “super ego” or other non-existing things.
For more on consciousness: Consciousness and no-self (explained in drawings)
PS: Nibbana is pleasant not neutal. It is difficult to understand why it could be so while still imagining some form of consciousness in nibbana. (and therefore not understanding it) It seems paradoxical, but it is not after a proper understanding. There is even a sutta explaining that.