You got me with the baby picture! She's absolutely adorable!
For the boot, I personally don't mind duplicates where I love something. However, I always feel like the second choice gets a lot less wear and a lot less love than the first. With that said, I have a pair of simple, very plain, flat knee high boots from JCrew that I bought about 6 years ago. They have an almond toe, so not too round, not too pointy. I love them, they've been a great investment, and I really really really wish that I'd bought them in black too. The other side of the coin is that I have a pair of black ankle boots that I adore too, and they get a lot of wear when I want to switch it up from a knee high.
I'd probably buy them in your size in black, let them sit for a while (you can return them for a full year to Zappos, so that makes sitting back a little easier) and see if you keep finding yourself wishing you could crack them out, or whether you feel like they can go back without causing you too much pain. I notice (and I'm sure that Zappos has noticed!) that I feel a lot more pressure to buy when I think they might sell out. Maybe that pressure is working on you too?