I'd recommend incontinence pants not just pads for :
Post birth
Post mc
Diarrhoea (you or the kids)
They're very comfy and if you're ill/weak just throwing away rather than accumulating laundry that may need hand soaking is much easier.
For vomitty people (children ok enough to cope with this and adults)
Plastic carrier/small bin bag lined with news or kitchen paper, again just throw after use or cheapo tea towels
Re swimming hot water bottle a bit cumbersome I used a couple of those cracky hand warmer things.
That post also reminded me (and again top tip for adults/older kids too)
When putting your stuff away in the locker make sure towel/shampoo/conditioner on top so you don't get other stuff wet hunting for em!