Sounds like you're well on your ways to being sorted ladies! I'm extremely glad I kept everything from the bigger boys as it's already ready to go, just need to get it all washed! No idea where I'll put everything
The only major thing we're missing is a cot, but that's because we've opted for a Next To Me instead. As I had bonding issues with DS2, I want to try and be as physically close to this baby as much as I can. We'll probably get a cot when he's a bit more mobile and the Chicco is no longer safe.
Debating over a buggy board for DS2 but we don't tend to use the buggy a whole lot. It was our biggest waste of money but was needed with a 14 month age gap. I like to imagine I'd use it more once we move to a house, but I doubt it as I really do despise walking

I don't envy the pram/travel system hunt that you'll be doing ladies, mine drove me absolutely bonkers with trying to figure out what was best for us.
I do find that sleeping bags are too big for teenies when they've first arrived, as their necks aren't very big they can wriggle themselves down into the bag. I've only tended to use them from about 6 months onwards, when they're a big chunkier. That being said, DS2 absolutely hated his and ended with a toddler duvet at 9 months as it was the only way to get him to sleep!

They're certainly unique, these small humans! Maybe consider the Grobag's 1 tog ones for summer sleeping, and I think they do bags from teeny weeny baby sizes too, whereas Asda, Tesco, Ikea, et al. are all 6 months+
Misskth, congratulations on a pink bundle! Thank goodness for that, it must have been driving you crackers wanting to know and being thwarted each time.