@Sleepyquest I've never heard about increased movement being an issue, I thought all movement was good! That seems unusual advice.
With the hospital bag, I'd definitely have separate ones for you and baby. Plenty of nappies, babygros, wipes and muslins in baby's, plus spare carriers for dirty clothes for you both.
Some people take snacks and drinks in with them for during labour. I couldn't keep anything down but everyone's different. Mothercare do black nighties with poppers all down the front which were great (until I vomited and leaked waters through all 3 of them haha). If you're having a waterbirth some people wear half a bikini but I wouldn't care myself!
Take plenty of big black pants (high-waisted ones will cover c-sections), plenty of pads as you will bleed for weeks, nipple pads, a dressing gown (again mothercare are good and dark ones are better in case of leaks) whatever clothes you are comfiest in for after the birth and going home, again if you have a planned or emergency c-section you don't want jeans or anything that will rub that whole area.
I'd recommend cheapy flip-flops for the shower, toiletries, hairbrush, hair bands and your own towel.
Phone charger definitely. All other stuff is optional like music, tens machine, books etc. It kind of depends how long you're in and if anyone will be available to pop home for you. I do know that the longer you're in the harder it is to stay organised with your stuff! That's why I'm all about the packing cubes this time 
Oh and your maternity notes.
Small detail 