Question on windows cluster

Hi Experts,

I am new clusters. But I have to support win 2003 clusters in my environment. I know it is deprecated but asking as we are still supporting win 2003 cluster environments.

Assume I have 2003 three node cluster(N1,N2,N3) and quorum model is disk only.
Here are some of my questions. Appreciate your response.

Question 1. If I have dedicated private network and if it goes down. What happens to the cluster? while it be up n running or what happens behind the scenes?

Question 2. If I have diff private network and public network and both configured for all communications, then if private network goes down, then will it fallback to public network. I mean now both private and public communication happens on public network only. And I am assuming cluster will still be up n running and we need to fix the private network in the mean time. Is that correct?

Question 3: What kind of error messages do we see if the private network/heartbeat goes down in the Windows Event logs.

Question 4: what are the best practices to configure network on clusters.

Thanks,
Sam