The baby shouldn't be too much of a problem once you get into a routine. Feed, change and play with it before your sims go to bed so it won't become lonely and cry in the middle of the night. Make a separate nursery so even when it does cry at night, it doesn't wake your sims up, and you can instead pick which sim you want to wake up to care for it. Buy your sims a better bed - it'll mean they need less sleep. Even with a low quality bed they shouldn't need more than 8 hours or so a day.
The skills needed to make ambrosia are level 10 cooking, fishing and gardening. If you've got at least one skill point in these, they can be further learned by watching TV. "Cooking cable", "Fishing fracas" and "Got garden?" are the respective stations. You'll need a decent TV to have access to those channels, though. You can also learn these skills by reading books, either at the library or by purchasing them from the bookstore. Cooking and gardening can also be done on your home lot, as can fishing if you edit your house to put a pond in. So you can still learn these skills even with a baby in the house. If you want to age up the baby, just buy a birthday cake from "outdoor activities", click on it, and choose the baby to blow out the candles. It will then age into a toddler.