Love the buttons but save them for when the babies two and older, three and up, is even safer. they pose a choking hazard, it's just too easy for little ones to put them in their mouths.
I intentionally sized the patterns in Soft + Simple knits for little ones to be for six months and up. Seems like those newborn sizes don't last for long. If you're taking the trouble to make something it's nice to know it'll be worn for awhile.
Good Luck, love to see what you end up making!

Huh, can you tell I don't have children of my own? Thanks for the heads up on the buttons! I'll save the idea for a project down the road.

You should definitely check out Heidi Boyd's Soft + Simple Knits for Little Ones. It has tons of ideas, and they're all really quick to knit. It has a few cardigan-type patterns...there's this zip-up vest that's really cute! And people have already been knitting the Swing Jacket on Ravelry. Plus there are tons of toy patterns.

Also check out the chapter on Wee Ones in Hannah Fettig's book, Closely Knit. There is a really precious cardigan with intarsia ducks on the pockets...a tiny vest with a kangaroo graphic, plus darling pants with heart patches on the knees.

Maybe we can share some baby patterns as the free patterns soon! Or possibly a baby knitalong?? I have been doing a lot of knitting for babies, too, and there's some more of it on the horizon...