I am only familiar with a limited set of critters (rat, cat, primate, corvid) in regards to the mammal and avian brains. As far as I know, this is a common layout for all of them; the limbic system is well preserved though the mammal family.
While we are at it - how about the amygdala?
@gmirey may be able to shed more light on this question.
As far as “working” this is an interesting question. Patient HM lost his hippocampus after forming a working set of memories. He was not able to form new memories but from what I have read he was able to talk and reason without a functioning hippocampus. I imagine that this would not have worked as well in an infant without working memories to draw on to survive.