As far as the mulitverse is concerned, I was under the impression that post-IC, the multiverse exists again.
I remember glancing through Wildstorm's Batman/Planetary ("mature" readers only), which gives an explanation of post-crisis DC. The rest of the multiverse exists while only a few universes were violently consolidated into one. Post-Infinite Crisis appears to create a multiverse within a singular universe. Frankly, I find this to be more confusing.