I was there but my pools were 12-2pm and I didn't stay past that so that's the limit to what I can comment on, but-
Room where MK11 was felt fine and cool enough with the AC. The AC in the rest of the building also felt fine so worst case you just stepped out of the room for a minute. Towards the end of pools it was getting a bit cramped though.
There was plenty of water available. Also no restriction that I could see against bringing your own water in their venue rules and nobody I could see telling people otherwise. No one even checked my bag let alone bug me about a water bottle.
The running of my pool felt sub optimal because it was getting crowded and therefore a tad hard to hear the pool runner call out matches, but not overly bad. It ran on time for me at least