One thing that you implied, but that I would like to make explicit is that

It is possible for separate parts of the blockchain can diverge and disagree, but using various criteria, the network consensus is discovered and eventually recognised by all nodes.

That consensus has a probability. Each block in the chain has a certain level of uncertainty surrounding the consensus of that block. The further back in the chain you go the less uncertain you are about the veracity of that block. An example is as you described where you would have a divergence of consensus on the latest block, until the network decides. Rinse and repeat.