Hi,
I had a water birth with both my boys.
May i suggest that you drop the yoga pants as not practical and opt for a big t-shirt or vest top. Also, drop the PJ's as you need easy acces with changing towels and throwing away disposable knickers etc... It's also easier with a nighty preventing any leaks as you can pop yourself straight on the maternity mats which they give you after the birth to stop any leaks onto clothes and sheets etc...
I wore a t-shirt bra in the water both times as a swimsuit is extremely impractical for obvious reasons. Blooming Marv do one by Carriwell.
Lansionoh Nipple Cream... just wack it on because they are gonna get sore and just incase purchase some Medela Nipple Shields if you incurr any damage due to bad latch on. I used them for 48 hours with my first just so that they could heal. I breastfed both boys for 8 months and none of them suffered with nipple/teat confusion. That is a load of bol*%$s.
Other than that you should prob add some energy drinks for yourself with a straw so that you can take quick sucks inbetween contractions.
I would also pack some energy bars that you can take quick bites from and some banannas too.
Oh and pop to Boots to get a bottle of Arnica tablets which encourage natural healing after the birth. When you get home use lavender oil and tea-tree for bathing which will be very soothing and healing if you incur any stiching on and around your 'bits'. The Midwife usually suggests this anyway and so will your Healthworker
Drop DH's change of clothes, you're the one whose been doing all the hardwork but do pack a button-down shirt for him to wear as it is easier for him to have skin to skin contact with his newborn afterwards. He could pack a toothbrush if he really wants to.
Have you decided whose responsibility charging the mobile phones and cameras is? And have you made a list of those you would like to contact first after the birth?
Just a thought.
Good Luck and hope some of the above helps you out x