Dear Blossom (if I have a ridiculous nickname so do you),
We all start out with a lot to learn, and I hate to say that the amount never goes down. Once you're certain you know everything about a baby, they start to walk. And then they start school, and before you know it they're off to Hogwarts (thank Merlin Ben isn't that old yet!) I do hope I can be of some help though. On the bright side, by the time Polly goes through certain stages, Ben will have already been through it.
Bugs are great sources of protein you know. There are cultures in the world that live on a primary diet of insects. And there are very few poisonous insects in England, and there are antidotes for all of them. So, if she should happen to eat a bug, don't worry about it.
I know a few handy soundproofing charms, that will still let in conversation and just mute the sound of the banging. I can teach you, if you'd like.
And you can always get down on the floor and play with her! Babies enjoy that, and when she gets older you'll be her favorite playmate. And I wasn't saying never to pick her up, as that is just impossible!
There are a few wizarding volumes, but...they're mostly on proper discipline, and non-fatal hexes to use on the wayward child. Very disturbing and horribly outdated.
And yes, I believe Abigail did supplement Ben's diet with cereal, but she was half Muggle herself. It's perfectly normal, however, as will be the fruits and vegetables you'll introduce her to in a couple of months. The cereal begins to get her digestive system ready for 'real food'. It's all in the books though, and explains it better than I am.
I know Ben would enjoy meeting you, and Polly as well. And yes, Ella is a wonderful friend of Ben's, and we always enjoy a play date. You'd all be more than welcome up at Hogwarts, and the walk up would be good for Polly.