Oh on the plans for DS, he'll probably go to the in-laws while I'm in labour. We're really lucky though that both sets of parents live about 30 mins drive away so my parents are on stand by too, but work more hours so less likely to be available. No chance of any parents taking time off (my Mum and FIL both work in schools so don't get time off) and MIL has to book her hols a ridiculous amount of time in advance! My Dad could in theory but he wouldn't be nearly as useful as a Mum!!! He might have to do though if I'm struggling when DH goes back to work.
As someone else said I'm really particular that I want DS to come home from the hospital with us, but I only want it to be the 4 of us when we get home so either DH will have to collect him before collecting us from the hospital or someone will drop him off at the hospital, but I've already explained that at least at first I want it to just be the 4 of us when we get home as I think we'll need just a bit of time to get used to it without it being a constant flow of visitors all over the house getting DS all excited and overwrought (yes, FIL, I'm looking at you!)
I'm hoping that certainly my parents (well, my Mum at least) will be helpful when they come to visit. My Mum seems to love nothing more than getting DS to help her with the cleaning when she comes now - i just leave them to it 
, so hopefully that'll carry on. She's a bit obsessed about getting DS 'involved' and helping with everything. MIL doesn't tend to offer to help with cleaning (I wonder if she' thinks it would seem a bit judgypants and as if she thought I wasn't keeping the house clean, which of course I'm not!). But last time I think they did some shopping and things for us.
I do recall last time though them coming round one night in the first week home from hospital. We'd got DS off to sleep (ish), DH had cooked me an iron rich spinach meal, my parents arrived. DH politely offered them a cuppa and they said 'oh, finish your dinner first' - I mean at least they didn't expect him to get up straight away but really, I mean they could have made their own flipping tea surely?
I know that's not much help Fishcake. It might be easier for DD to go with a friend if she knows them quite well? Do you have someone who would be happy to take her over night? Perhaps she could have a trial? It's so difficult to decide what to do and it's so emotionally charged that you don't want to offend anyone. I think too if you are having rellies to stay, I'd be tempted to get them to stay in a hotel (you can blame it on the mess of packing etc) and prime them with the sorts of things you'll need them to do while they're here - you know maybe helping with the packing or taking DD to the park or doing X, Y or Z that you'll struggle with because of the CS?
That way if the are still hopeless, at least you know you tried and they'll bugger off at the end of the day and you can have a rant with DH about it but have a nice rest. I think it's important to spend time just the close family too as you've all got some adjusting to do so it's important (I think) for our existing DCs to get a taste of what the new family mix is going to be like, without it being constantly diluted with relatives flitting in and out. So for us, bedtime is a really key time with DS when we have a strong routine etc, I know this is going to be really hard to maintain with a newborn etc, but I so want to try and keep it a 'special' time. It might be that it is special with all four of us, but I still want it to be 'our' time with lots of cuddles. I am also wondering if this is hopelessly naive!
Wow that was longer than I expected - my verbal diarrhoea strikes again 