You can't expect to keep the parcel shelf intact in such a scenario. In daily use, it's a neat thing to have and good for privacy, but it isn't compatible with gaining maximum capacity. Take it out and leave it at home, so you can pack up to the roof if necessary.
Obviously, make sure that things are jammed in such a way that nothing can fall forward over the top and hit your DD (or at least nothing harder than a duvet or pillow). Putting the larger 'half' of the back seat down will give you a much leveller area to work with. Again, obviously make sure that things won't fall sideways and hit your DD.
Apart from things like the tent, where you can't really help it, don't take suitcases or rigid-sided bags - you can fit so much more in if you have smaller, squashable bags.
Exploit the fact that your DD doesn't need to use her footwell yet and stuff it (along with the other one in the back) full - camping stoves, pans, tins and other heavy stuff are ideal to wedge in here. Also, don't overlook the area underneath the front seats before packing the actual footwells themselves - you can jam quite a lot of small things under there for a start (just don't forget they're there - especially if perishable!)
Also, if you have bulky but light items, you could consider one of those soft roofbags that strap to the roof or even a car backpack (yes, they exist!), which don't require a huge amount of storage space when not in use like a rigid roofbox. If you happen to have a towbar, but don't want the hassle of actually towing, you can get something that's like an extended bike rack (might not be cheap) that attaches to the back and could fit a few light-but-bulky bags on safely, with plenty of bungees to keep it all safely tied. In fact, a rigid big suitcase or two possibly WOULD be better if you went down that route.
You'll probably be fighting a losing battle as your DD gets older - especially if she has any siblings in due course. Yes, she won't need all of the massive baby stuff (although any siblings might), but you'll lose the footwell and she'll naturally replace it with loads of older-kid stuff - as well as wanting stuff to entertain her on the journey instead of just sleeping. Yes, it's good to pack minimally, but it seems a shame if she has to go on holiday and leave a load of her favourite toys and games behind.
Ultimately, wonderful though VW Golves (plural?!) are, you're probably not going to easily manage with it as your only/main family car - especially if you go camping - and you might need to swap it for a bigger one (maybe a Golf estate?!). If the car suits you for the rest of the year, you might need to look into a compact caravan (it obviously won't tow a big, heavy one). You can have an awning to maximise space, which will travel in the caravan, along with duvets, bedding, moon chairs(!) etc.
Alternatively, a folding camper, trailer tent or just a small trailer might be worth considering. Of course, that's assuming you have somewhere to store it or can afford to pay for storage.
Whatever you do, happy camping! And however stressful the packing and journey may be, keep telling yourself how much fun you'll all have once you're there and set up 