Heh! I asked quite a while ago here on this Space.com forum whether our universe has a "spin", and the result was mostly that it can't spin because there is no frame of reference against which to measure it.
But, like the "Coriolis Force" on our spinning Earth, the spin of our universe would have physical manifestations within, that could be measured - and now that is apparently being attempted. Hooray for that effort!
If indeed our "universe" is a black hole inside a bigger universe, then I think we need to recognize that energy and matter can still come in from the outside, just as we think that supermassive black holes in our universe are still taking in matter and energy, today.
So, what would that look like from the inside of the black hole? Perhaps like the CMBR?
It is hard to visualize the geometry of the inside of a black hole such that it appears to those on the inside to be expanding instead of contracting. But, I have read that solutions to the field equations of General Relativity Theory do predict that perception.