Hi There
I didnt end up wearing anything, i remember at the time I wish I had packed a tankini top, then the contractions kicked in and it was time to push and funnily enough it didnt cross my mind again!
1 - water was fine temp, hubby can top up when or if needed
2 - mid wife never got in, hubby didnt as he was there to get things if needed!
3 - I cant remember much gunk to be honest, water broke in there and still wasnt much. I chose not to give birth in the pool, once water broke and contractions were quciker got out and baby arrived pretty quickly
4 - didnt give birth in water on both occasions just choice, no reason not to.
I did remember thinking i wish I had bought something to rest my head on poss one of those inflatable cushions u can sucker onto the bath as at some points it was a bit uncomfortable, just a suggestion!
I had gas and air for both of mine and didnt need any more, the water makes a huge difference stayed in the bath at home for as long as poss, be careful not to have water too hot at home as when I got to hospital the poor babies heart beat was a little fast poss due to the high temp of water at home!
birth 1 - got to the hospital and was 9 cm just using the water as pain releif at home
birth 2 - didnt get checked or monitored just got in birthing pool and waters broke within 30 mins and got out baby arrived very soon after exit from the pool
I have been very lucky, didnt think I had a great pain threshold but I must have!
Good Luck!