Auto failover handling in cluster mode disabled Redis ElastiCache

I want to understand the failover case from the perspective of node endpoints https://forums.aws.amazon.com/, IP addresses for the cases

1. Master failover and replica gets promoted
2. Replica failover

The configuration is as Cluster mode disabled : Only 1 shard with (1 master and 2 replicas) with multi AZ enabled.For example -

PRIMARY ENDPOINT - xxx.dktrm8.ng.0001.usw2.cache.amazonaws.comREADER ENDPOINT - xxx-ro.dktrm8.ng.0001.usw2.cache.amazonaws.comNODE ENDPOINTS - {xxx-a.dktrm8.0001.usw2.cache.amazonaws.com -> master,xxx-b.dktrm8.0001.usw2.cache.amazonaws.com -> replica,xxx-c.dktrm8.0001.usw2.cache.amazonaws.com -> replica}

Ques -

1. Are the node endpoints are DNS names ?
2. Failover has been handled on IP address level or node endpoints level ?
3. After failover can primary endpoint point to different node endpoint(promoted master) or just the IP address mapping gets changed ?
4. If one is using node endpoints for read traffic instead of reader endpoint, is it possible that the node endpoint's role get changed to 'MASTER' ? in case of failover or maintenance.