Layman here. To your second bullet, yes, the universe can be infinite but also be expanding. A rough analogy I've heard is that there are infinite points on the

Layman here. To your second bullet, yes, the universe can be infinite but also be expanding. A rough analogy I've heard is that there are infinite points on the surface of a balloon, but if you blow it up more, the distance between any two given points will be greater than it was, so it has expanded. I don't think we know if the universe is infinitely large or not though.